Message on screen says ink cartridge problem remove and check cartridge - but cartridge is fine

Replacing Ink Cartridges
Make sure you have a new ink cartridge before you begin.
Caution:
Do not open ink cartridge packages until you are ready to install the ink. Cartridges are
vacuum packed to maintain reliability.
Leave the expended cartridge installed until you have obtained a replacement, or the ink
remaining in the print head nozzles may dry out.
1. Turn on the product.
2. If an ink cartridge is low or expended, you see a
message on the LCD screen indicating which
color to replace. Press OK.
If a cartridge is expended, you must replace it to be able to print or copy. If a
cartridge is low, you can continue printing until a cartridge needs
replacement.
If you're replacing a cartridge before you see a message on the LCD screen,
press xMenu, press u or d to select Maintenance, and press OK. Then
select Ink Cartridge Replacement and press OK.
3. Open the scanner, then open the cartridge cover.
4. Squeeze the tab on the cartridge and lift it up.
Dispose of it carefully. Do not take the used
cartridge apart or try to refill it.
Warning:
If ink gets on your hands, wash them thoroughly with
soap and water. If ink gets into your eyes, flush them
immediately with water. Keep ink cartridges out of the
reach of children and don't drink the ink.
5. Before you open the new cartridge package,
shake it gently four or five times. Then remove
it from the package.
6. Remove the yellow tape from the bottom of
the ink cartridge.
Caution:
Do not remove any other labels or seals, or ink will
leak. Do not touch the green chip on the front of
the cartridge. This can damage the ink cartridge.
7. Insert the new ink cartridge into the holder
and push it down until it clicks into place.
8. Once you replace all the cartridges that need replacing, close the cartridge
cover and push it down until it clicks into place.
9. Close the scanner.
10. Press OK to begin charging the ink. This takes
about 2 1/2 minutes. When you see a
completion message on the LCD screen, ink
charging is finished.

Caution:
Never turn off the product while ink is charging or you'll waste ink. If you see an ink
replacement message on the LCD screen, press OK and press down all the cartridges
securely. Then press OK again. If you remove a low or expended ink cartridge, you
cannot reinstall and use the cartridge.

See Page 47 in manual
Download Manual Here

If you do not want to go through the guide, here is a quick instruction on how to insert the ink cartridge.
Remove and Install Cartridges Be sure you have your replacement cartridges handy before you begin. You must install new cartridges immediately after removing the old ones. Caution:
Do not open ink cartridge packages until you are ready to install the ink. Cartridges are vacuum packed to maintain reliability. If an ink cartridge is low or expended, you see a message on the WorkForce 310 Series LCD display screen indicating which color to replace. Press OK. If you're replacing a cartridge before you see a message on the WorkForce 310 Series LCD display screen, press the Copy button, press Menu, press or to select Maintenance, and press OK. Then select Ink Cartridge Replacement and press OK. 1. Open the scanner, then open the cartridge cover. 2. Squeeze the tab on the cartridge and lift it up. Dispose of it carefully. Do not take the used cartridge apart or try to refill it. Warning:
If ink gets on your hands, wash them thoroughly with soap and water. If ink gets into your eyes, flush them immediately with water. Keep ink cartridges out of the reach of children. 3. Before you open the new cartridge package, shake it four or five times. Then remove it from the package. Caution:
Do not touch the green chip on the front of the cartridge. This can damage the ink cartridge. 4. Remove the yellow tape from the bottom of the ink cartridge. Caution:
Do not remove any other labels or seals, or ink will leak. 5. Insert the new ink cartridge into the holder and push it down until it clicks into place. 6. Once you replace all the cartridges that need replacing, close the cartridge cover and push it down until it clicks into place. 7. Close the scanner. 8. Press OK to begin charging the ink. This takes about 2 minutes. When you see a completion message on the LCD display screen, ink charging is finished. Go through your user manual for further guide on how to install ink.

1 Remove and Install Cartridges Be sure you have your replacement cartridges handy before you begin. You must install new cartridges immediately after removing the old ones. Caution:
Do not open ink cartridge packages until you are ready to install the ink. Cartridges are vacuum packed to maintain reliability. 1. Turn on the Epson Stylus CX8400 Series. If a cartridge is low or expended, you see a message on the Epson Stylus CX8400 Series LCD display screen. If a cartridge is expended, you must replace it to be able to print. If a cartridge is low, you can continue printing until the cartridge needs replacement. If you're replacing a cartridge before you see a message on the Epson Stylus CX8400 Series LCD display screen, press Setup, select Maintenance, and press OK. Then select Change Ink Cartridge and press OK. 2. Open the scanner. 3. Open the cartridge cover. 4. Squeeze the tab on the cartridge and lift the cartridge straight up to remove it. Dispose of it carefully. Do not take the used cartridge apart or try to refill it. Warning:
If ink gets on your hands, wash them thoroughly with soap and water. If ink gets into your eyes, flush them immediately with water. Keep ink cartridges out of the reach of children. 5. Before opening the new cartridge package, shake it four or five times. (Do not shake a cartridge after opening the package; ink may leak.) 6. Remove the cartridge from the package, but be careful not to touch the green chip on the cartridge. 7. Remove the yellow tape from the bottom of the cartridge. Caution:
Do not remove any other labels or seals, or ink will leak. 8. Insert the new cartridge into the holder and push it down until it clicks into place. 9. Once you replace all the necessary cartridges, close the cartridge cover and push it down until it clicks into place. 10. Close the scanner. 11. Press OK to begin charging the ink. This takes about 2 minutes. When you see a completion message on the LCD display screen, ink charging is finished. Caution:
Never turn off the Epson Stylus CX8400 Series while ink is charging or you'll waste ink.
If you see an ink replacement message on the LCD display screen, press OK and press down all the cartridges securely.

Hi,

Check two things

1. Ink in your catridge

2. Check whether the catridge has been proprely inserted because some movement to the printer may cause the catridge postion to be misplaced

Hope your problem got solved

Please rate my solution

Thank you

1. Turn on the Epson Stylus CX8400 Series. If a cartridge is low or expended, you see a message on the Epson Stylus CX8400 Series LCD display screen. If a cartridge is expended, you must replace it to be able to print. If a cartridge is low, you can continue printing until the cartridge needs replacement. If you’re replacing a cartridge before you see a message on the Epson Stylus CX8400 Series LCD display screen, press Setup, select Maintenance, and press OK. Then select Change Ink Cartridge and press OK. 2. Open the scanner.
3. Open the cartridge cover.
4. Squeeze the tab on the cartridge and lift the cartridge straight up to remove it. Dispose of it carefully. Do not take the used cartridge apart or try to refill it.
Warning:
If ink gets on your hands, wash them thoroughly with soap and water. If ink gets into your eyes, flush them immediately with water. Keep ink cartridges out of the reach of children. 5. Before opening the new cartridge package, shake it four or five times. (Do not shake a cartridge after opening the package; ink may leak.)
6. Remove the cartridge from the package, but be careful not to touch the green chip on the cartridge.
7. Remove the yellow tape from the bottom of the cartridge. Caution:
Do not remove any other labels or seals, or ink will leak.
8. Insert the new cartridge into the holder and push it down until it clicks into place.
9. Once you replace all the necessary cartridges, close the cartridge cover and push it down until it clicks into place.
10. Close the scanner.
11. Press OK to begin charging the ink. This takes about 2 minutes. When you see a completion message on the LCD display screen, ink charging is finished. Caution:
Never turn off the Epson Stylus CX8400 Series while ink is charging or you’ll waste ink.
If you see an ink replacement message on the LCD display screen, press OK and press down all the cartridges securely.

If you remove an ink cartridge for later use, protect the ink supply area from dirt and dust and store it in the same environment as the Epson Stylus CX8400 Series with the label facing upward. Note that there is a valve in the ink supply port, making covers or plugs unnecessary, but care is needed to prevent the ink from staining items that the cartridge touches. Do not touch the ink cartridge ink supply port or surrounding area, and do not store the cartridge upside down.

If you remove a low or expended ink cartridge, you cannot reinstall and use the cartridge.

got this from the Epson Site

Check and make sure you did buy the right one first.

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/edwy_1a56970cf1ea4620

Make sure you have a new ink cartridge before you begin. You must install new cartridges immediately after removing the old ones.
Follow the steps below to replace one or more ink cartridges that are expended:

1. Turn on the printer.
2. If a cartridge is low or expended, you see a message on the display screen. Note which cartridges need to be replaced and press OK.
3. Open the scanner, then open the cartridge cover.
4. Squeeze the tab on the cartridge and lift it up. Dispose of it carefully. Do not take the used cartridge apart or try to refill it.
5. Remove the cartridge from the package, but be careful not to touch the green chip on the edge.
6. Remove the yellow tape from the bottom of the ink cartridge.
   
   Caution: Do not remove any other labels or seals, or ink will leak.
   
   
7. Insert the new ink cartridge into the holder and push it down until it clicks into place.
8. Once you replace all the cartridges that need replacing, close the cartridge cover and push it down until it clicks into place.
9. Close the scanner.
10. Press OK to begin charging the ink. This takes about 2 minutes. When you see a completion message on the display screen, ink charging is finished.

Caution: To conserve ink, never turn off the printer while ink is charging. If you see an ink replacement message on the display screen, press OK and press down all the cartridges securely

Remove and Install Cartridges Be sure you have your replacement cartridges handy before you begin. You must install new cartridges immediately after removing the old ones. Caution:
Do not open ink cartridge packages until you are ready to install the ink. Cartridges are vacuum packed to maintain reliability. 1. Turn on the Epson Stylus CX8400 Series. If a cartridge is low or expended, you see a message on the Epson Stylus CX8400 Series LCD display screen. If a cartridge is expended, you must replace it to be able to print. If a cartridge is low, you can continue printing until the cartridge needs replacement. If you’re replacing a cartridge before you see a message on the Epson Stylus CX8400 Series LCD display screen, press Setup, select Maintenance, and press OK. Then select Change Ink Cartridge and press OK. 2. Open the scanner. 3. Open the cartridge cover. 4. Squeeze the tab on the cartridge and lift the cartridge straight up to remove it. Dispose of it carefully. Do not take the used cartridge apart or try to refill it. Warning:
If ink gets on your hands, wash them thoroughly with soap and water. If ink gets into your eyes, flush them immediately with water. Keep ink cartridges out of the reach of children. 5. Before opening the new cartridge package, shake it four or five times. (Do not shake a cartridge after opening the package; ink may leak.) 6. Remove the cartridge from the package, but be careful not to touch the green chip on the cartridge. 7. Remove the yellow tape from the bottom of the cartridge. Caution:
Do not remove any other labels or seals, or ink will leak. 8. Insert the new cartridge into the holder and push it down until it clicks into place. 9. Once you replace all the necessary cartridges, close the cartridge cover and push it down until it clicks into place. 10. Close the scanner. 11. Press OK to begin charging the ink. This takes about 2 minutes. When you see a completion message on the LCD display screen, ink charging is finished. Caution:
Never turn off the Epson Stylus CX8400 Series while ink is charging or you’ll waste ink.
If you see an ink replacement message on the LCD display screen, press OK and press down all the cartridges securely.

If you remove an ink cartridge for later use, protect the ink supply area from dirt and dust and store it in the same environment as the Epson Stylus CX8400 Series with the label facing upward. Note that there is a valve in the ink supply port, making covers or plugs unnecessary, but care is needed to prevent the ink from staining items that the cartridge touches. Do not touch the ink cartridge ink supply port or surrounding area, and do not store the cartridge upside down.

If you remove a low or expended ink cartridge, you cannot reinstall and use the cartridge.

http://h10025.www1.hp.com/ewfrf/wc/genericDocument?docname=buu02180&cc=in&lc=en&dlc=en

I resolved the "remove and check cartridge" issue after reading the instructions at the above address. Most importantly, I replaced both cartridges and the problem was resolved.
The color cartridge appeared to be the issue. It had been in for months and used infrequently.