Means yourn ISP has blocked you from sending that e-mail out, it could have matched too many keywords that set off there spam blocker. Reword your e-mail and try again, if not call your ISP as they should know what they have set to block

Thank you very much for the response...all outgoing email is being blocked for "too much spam"...even "test" msgs that have nothing in the subject line or msg portion.

The previous suggestion has assumed that your ISP is also your email provider.

If you're using an email provider who is independent of your ISP, your email provider may be blocking messages sent from your ISP's network. In this case, you should tell your ISP about it so they can work to have themselves removed from whatever blacklist that they have been added to.

OTOH, if your ISP and email provider are one and the same, they really ought to have told you they have blocked you and should be offering to help you sort out what is wrong with your messages that has led to your being blocked.

So: who is your ISP? Who is your email provider?

ISP and email provider is COMCAST. They claim that the blockage was not a blockage but part of a larger email system problem of which my account was only a part. 90 minutes ago they said the problem would be corrected in an hour.. So far, not.

Thanks for the input.

4th day with no outgoing email and Mozilla has not addressed the problem.

re: ISP and email provider is COMCAST. They claim that the blockage was not a blockage but part of a larger email system problem of which my account was only a part. 90 minutes ago they said the problem would be corrected in an hour.. So far, not. .......Mozilla has not addressed the problem Your ISP has acknowledged that the issue is their fault. So, it seems this has nothing to do with Thunderbird. Have you contacted Comcast to say things are not resolved?

I use both OUTLOOK and MOZILLA/Thunderbird for e-mails. Comcast webmail works fine as does OUTLOOK. Mozilla does not have a helpful service dept. Only solution appears to be to uninstall and then reinstall MOZILLA/Thunderbird. I hate to do this as I don't want to lose emails stored in my folders. MOZILLA/Thunderbird doesn't seem to have a similar facility for saving folders en masse as OUTLOOK does.

Thanks you for your suggestions.

It is unlikely that un/re-installing Thunderbird will help. But all your data is stored in your profile. Back that up, keep a copy and if it all goes south you can revert to where you are now.

https://support.mozilla.org/en-US/kb/profiles-where-thunderbird-stores-user-data