The error is from your email provider. The message states "the mail server". Thunderbird is just the messenger.

Delete old messages in ALL folders including Trash and Spam. Compact folders to finish the cleanup.

If that does not fix, contact your provider.

Thanks, I have tried this to no avail so have gone back to them again as they keep sayings its Thunderbird even though I said it wasn't ? Thank you !

Ask them why THEIR server is doing the complaining if it is a Thunderbird issue?

I reread your first post and you mentioned sending from webmai. Do you get this message when sending from Thunderbird? If so that would indicate that your provider thinks you send too much mail and not a disk storage problem.

Thanks, They are now saying it's due to being over a quota of emails ...I think they possibly read your message :) Apparently it should be resolved soon... we will see. Many thanks for your help !

It always amazes me when the email provider "helpless" desk agents try to claim it is not their problem when it is THEIR server issuing the error message. But then, all they know is to pick up the phone if it makes a noise and read a script.

One "false positive" that can occur with quota errors is if you are not actually logged into the server. I Think it might be an idea if you posted you troubleshooting information so someone can see you account settings.

Could you please do the following:

1. Open the menu > Help > Troubleshooting Information, then click Copy text to Clipboard.

1. Open a reply to this post, and paste your troubleshooting information.