Did it work with local MMS? Also, when you send MMS, was the outgoing number formatted correctly (with proper country code)?

The Canadian MMS works perfectly. 

The numbers are fine, they get my text messages abroad using those numbers. 

(Google Pixel 6, the right APN and all - proof is the MMS working nationally).

So what was the exact error message that you saw? Was there any indication on the message app chat. By the way, are you and other people using RCS?

Most of the time there is no message at all.  But the “delivered” tag never appears.  I forgot to say that I don’t receive images from abroad either… 

I guess I should just drop it. In fact, it never worked on the last 10 years of Koodo, no matter the phone I used. I just asked again with the hope that someone came with a solution in the meantime.  It’s not the case. 

Thanks!

If you saw the “delivered” status, that was RCS, not MMS. I recommend you turn RCS (chat) off to see if it can hdlp.
If there was no error message from Koodo, the message might have been sent. The issue could be people from other end

I get the “Sent” message, but never the “Delivered”.  So you might be right, it could be something on the recipient's side.  

Back to Signal, I guess… 

That was definitely RCS. MMS is the old communication protocol, didn't have any status report.

So it is clear. People on the other side of the pond are mostly Apple. And iPhone doesn’t play well with RCS.