I am getting "Authentication Problem" with WiFi on 2 tablets - excellent signal. Accepts the security code and will hold for a minute or so.

I'd make sure that you have configured the correct wireless security type. If your tablet allows both WPA and WPA2, make sure whatever you selected matches the configuration on your WiFi router. Also, the encryption algorithm has to match - AES is the most common but some older routers only support TKIP.

This can happen when you are using a new wireless security authentication and a older device such as 2.3

We would suggest two thing
1. No Reset button,1)You have to press power and volumen up @ same time and realese power when turn on.2)presspower and volume up and select wipe.

2. going to a different type of security on your router to see if you have success.

I’m happy to help further over the phone at https://www.6ya.com/expert/jonathan_828b54f422cbefdd

Hi
To connect to a WiFi system, you may need 3 pieces of information:
A username
A password
An encryption key
Once you have successfully linked to a WiFi access point then your tablet will remember the settings until told to forget them.
A lot of the time you may only need the encryption key, and if the tablet detects a WiFi access point then if you tap on that in wireless settings then it will either connect automatically or ask you for some sort of code - the encryption key. If this is not entered correctly then it will return an authentication problem/error. In order to connect you have to have this code. Also bear n mind that the code may or may not be case sensitive, and that the authentication type for both router and tablet needs to be the same. It is possible that you will only be able to change the authentication type on the Aceess Point / router and not on the tablet.
Cheers

Try to change the wifi security to a lower level, or remove the server from your tablet and re-do the process to login.

Here is the remedy for that error:
We've heard a few reports of Wifi connectivity issues recently, among them 'Authentication error'. If you receive this message, our recommended remedy is to remove all Wifi connection information from your Meep, turn off your Meep, reboot your router, then turn on your Meep and re-add the Wifi information. Follow these steps exactly in this order to resolve this error message:
1. Remove all Wifi network information from the Meep's settings
2. Reboot your router
3. Re-add the Wifi network information to the Meep's settings
4. Reboot the Meep.

wrong settings entered on tablet, try again.If possible connect tablet first via usb cable to computer or router to try connecting it , to determine the actual fault on connections.

Maybe try going to the router settings and changing the security settings. See if turning off wifi password solves the problem then turn it back on.

Turn off or WiFi wait five minutes then turn WiFi back on it worked for me

Can't get unit to connect to my home wifi , keeps giving message Authentication Problem