Magento 2.3.3 not sending any mails

Question

My Magento 2.3.3 is not sending any emails from the solution.

As far as I can see, the cron job is running, the mail settings looks fine and are enabled.

I think I have tried it all, but no luck, it keeps saying "The order confirmation email is not sent".

I have tested if I can send a mail from a PHP file, and that works just fine.

Do anyone, have an idea?

Answer 1

Potentially the mail extension combined with a compatibility issue on 2.3.3 has broken it

Magento 2.3.3 mail not working

https://community.magento.com/t5/Magento-DevBlog/Backward-incompatible-Changes-in-the-Mail-Library-for-Magento-2/ba-p/144787

https://magento.com/tech-resources/download#download2333

Try the official patch (last link) first. The first two links are for information. The first one demonstrates the type of messages you should be seeing in the exception log. The second post details what went wrong.

Just directly apply patch. Cant use composer.

EmailMessageInterface backward compatibility issue patch for Magento 2.3.3