Mailbox is full how do you empty it? - AT&T DECT 6.0 Cordless Phone System with Digital Answering Machine

https://www.manualslib.com/manual/303940/Panasonic-Kx-Tg7622b.html?page=60#manual

that means that your mailbox is full, empty it on the phone memory and the sim memory.....

Samsung Galaxy S5 How to Delete Old Junk Emails in Inbox

hope that helps

With Webmail, you need to empty the Trash folder. With Thunderbird, Mail, OE, Outlook, or another mail program, you need to change the Account settings to remove the mail from the server when deleted.

If this is a problem with a the mailbox on a phone, you posted to the wrong category, "Problem with PC Desktops" and should possibly call the phone provider for instructions, default password, etc..

Call your phone company

Call your number and enter your voicemail password, then make sure all the messages are deleted.

home button on pad menu pops up click on delete another menu pops up choose from list you want to delete or just tick box. then delete.

You can open messages and choose the option to MARK all the messages on the BOX -ONLY if you want to delete them all.
Once marked choose the option to delete them fully.

there is a system to delete mailbox in manual book u can use it or in mail box after selecting option u can find erase or delete option choose it click on yes u can delete ur mail

Problem resolved