Cannot download emails from email server sites (e.g., Gmail).

Hello,
Suddenly today, the Thunderbird stopped downloading emails from an email server site (in my case Gmail) w/ the following message.

"!!! The folder inbox is full, and cannot hold any more messages. To make room for more messages, delete any old or unwanted mail and compact the folder. [OK]"

Even after deleting 1000s and 1000s of emails, the error message is the same, and I still cannot download any more emails.
Isn't it maybe, one of the email files became corrupt and lost [EOT], so the TB sees the file to be infinitely big.

Is there a way to upload a face shot of the error message, so you can clearly see what the problem is?

Could you help me resolve this problem?

Thanks.