Hello there seadog7984 We have read your message. We try to help you.

Oké it seems that you have got a rebounce of the server at your mail box with a spam message with it. spam OB703. We try to help you with this issue.

Try first to start up in safe modus for Thunderbird.

https://support.mozilla.org/en-US/kb/troubleshoot-mode-thunderbird

if the problems disappear after entering safe mode. Now check if you have add ons installed . if so try disabling it.

After doing this it’s time to ask you a couple of questions.

Greetings Firefox volunteer

I have disabled add ons and restarted in safe mode. Problem is still there.

Hello there seadog7984.

Oké after turning and switching the add ons on and of there s no change in this issue.

Let me ask the questions to solve this unable to send a message with Thunderbird.

What version do you us from Thunderbird? Are you using windows? Do you have internet security running yes what ? Do you use fire walls?

Try to delete your current version of Thunderbird software and replace it for a new version. The new full version is down below to reinstall again.

The issue has to be disappeared. Make some backups from your passwords and settings. https://www.thunderbird.net/en-US/thunderbird/91.9.1/releasenotes/

Greetings Firefox volunteer.

I am running Thunderbird 91.9.1, using Windows 10 and using Kaspersky Total Security (including firewall). I have uninstalled and re installed Thunderbird. Still no change.

Hello there seadog7984.

The situation is not improving oke. Make a new try to delete all.

Take another step to delete all profiles of your Thunderbird on your computer or multiple computers so that everything can be renewed with a new installation that I sent you this should be the way to send a message without any problems. Also use cleaning software such as CC Cleaner. To also remove testants on your computer pc. so that it is completely clean of any trace of our Thunderbird software.

I will send you another form to read this for not being able to send emails. With Thunderbird email software.

In meanwhile check your Smtp settings for Thunderbird. Contact me after trying these steps.

https://support.mozilla.org/en-US/kb/cannot-send-messages

Try to keep your security software on and disable your firewalls. Greetings Firefox volunteer.

Hello there seadog7984.

https://support.mozilla.org/en-US/kb/manual-account-configuration

The settings for your Smtp settings for the Thunderbird configurations has to be.

the outgoing server port: 465 or 587 Security Ssl or Start SSL.

Greetings Firefox volunteer.

Thank you for your help. I got a tech in to solve the problem as some of the documents I was sending were time sensitive. Appreciate your efforts to help a a tech confused old guy.

re :Sending of the message failed. An error occurred while sending mail. The mail server responded: 626F290E04D8BA88 Message content rejected due to suspected spam. OB703. Please check the message and try again.

It is a message from the server. They have a spam filter operating and it is rejecting your emails.

re: I have uninstalled and re installed Thunderbird.

As that message has nothing to do with the Thunderbird program, this would be futile.

One possible reason could be you are using insecure methods of sending.

So smtp outgoing would need to use: Either : Connection Security : SSL/TLS and port 465 OR: Connection Security: STARTTLS and port 587

Check to see if Your Anti-virus is scanning and adding a load of links. Easy way is to restart computer in 'Safe Mode with Networking' and then start Tunderbird. Send emails to test.

Hi googlethunderbird I notice you are using a cut down image originally created by me :)