M5216 message waiting - Nortel Networks M5216 Phone

https://www3.bellmts.ca/mts/support/phone+services/troubleshooting/you+have+no+new+messages+waiting+but+your+phone+says+you+do

Turn off Message Waiting Notification temporarily

1. If you know you have a message waiting, but do not wish to retrieve it immediately, you can turn off Message Waiting Indicators.
2. Press *93 to turn off the flashing light and stuttered dial tone until another message is received in your mailbox.

Message Waiting Indicator Your phone's message waiting indicator is either a light or special tone that alerts you when you have voice mail.

Occasionally, the message waiting indicator may be out of sync with your mailbox. In that case, the indicator light or tone is ON but there are no messages waiting, or the indicator light or tone is OFF when there are new messages waiting.

To get the message indicator back in sync

1. Save or delete all new messages
2. Hang up.
3. If the message indicator does not go out or stop within a few minutes, there may be a problem, and you should contact Verizon.
4. If the message indicator does go out or stop, call your own number and leave a message
5. Hang up and wait
6. If the indicator light or tone does not come on within a few minutes, there may be a problem, and you should contact the vender.

See page 16 of the document below, however whether that works depends on how the centrex system is programmed.
http://www.bu.edu/tech/files/2009/09/M5216userguide.pdf

press feature #65

There is another reason you are having the message waiting indicator besides having a message waiting, it also means the phones messages are full and some messages need to be deleted. Once you have deleted some messages, then you will be able know if you have any message waiting or its just a symbol to show that your message is full.
Hope this information helped

That is the message waiting indicator, it is telling you that your Call Notes (Or whatever your service provider calls it's voicemail) has a message waiting. If you do not have a message waiting, you can turn the light of by following these steps:

Resetting the voice message waiting indicator
When you receive a new voice mail message, the new message LED on the top of the handset flashes and
appears in the handset display. In the event your message waiting light gets out of sync with your phone company’s
voice messaging system, you can manually reset it back to the “No messages waiting” state.
Press and hold FIND on the base for five seconds.
Note: The handsets connected to the base will start to beep, however, keep pressing for five seconds.
A beep sounds and the message alert tone is reset.

This feature is country dependent and may not
appear in some countries.
If you have subscribed to the voicemail service
from your local service provider, icon turns
on when you have a new message in your
mailbox. After you have accessed to all the new
messages, icon will turn off automatically. If
you find that the message waiting indication
cannot be turned off by the network, you can
still turn off the message waiting indication with
your phone by the following step :

In idle mode, if voice mail waiting icon is on,
long press the redial key to turn off the voice mail waiting
icon.
Once you choose to delete the message waiting
indication, all the other handsets registered to
the same base station will turn off the message
waiting indication accordingly.

i log in to my email and it tells me how many email i got but when i click on it, it gives me all these login error message and i click okay button the screen gets a loading message and i wait and wait and wait but nothing happen and i just want to check my mail

Go into the voicemail, press 5 for message waiting notification options, press 1 for message waiting light status.

The term we used for this back when I worked for the phone company was a "stuck message waiting indicator" and the way to fix it was:

Call yourself and leave a message.
Hang up and wait 2 minutes (we used to say 5 minutes, but 2 is plenty)
Retreive/delete your voice mail message
Hang up and wait 2 minutes


That should clear the blinking light.