I could not receive or send image from Pixel 3 by message. Do you have the same issue?

It seems to be an APN problem

https://fizz.ca/en/faq/what-are-fizz-network-settings-apn

Definitely follow the steps as per Fizz's FAQ

https://fizz.ca/en/faq/what-are-fizz-network-settings-apn

Also this seemed to help in my case. Edit manually both APN settings to change "APN protocol" and "APN roaming protocol" to "IPv4/IPv6"

Data has to be turned ON to send or receive MMS.

Oh I had that problem also ! Thanks @Zizzy!

If the APN did not solved the problem, contact the support

To chat with the support, make sure that:

• You're logged into your Fizz account.
• You're active on a help page.  https://fizz.ca/en/contact-us
• You're within the business hours: Monday to Friday from 8 a.m. to 9 p.m. (EST), weekends and holidays from 10 a.m. to 6 p.m. (EST).
• You have disabled any ad blockers in your browser.

If the chat bubble does not appear, this means that the number of sessions waiting for our answers surpasses our processing capacity. If that happens, send us a private message via Facebook Messenger or Twitter.

I also have the same issues with my pixel 3!

Verify that the APN settings are typed correctly and you didn't accidentally replace a dot with a comma etc. Then reboot your phone and test again, it's very likely an issue with the APN settings

Fizz APN settings are:

APN: mobile.bm
MMSC: http://mms.mobile.bm
MMS proxy: mmsproxy.mobile.bm
MMS port: 80
APN type: default,mms,supl

Copy and paste it! For me it worked!

I've heard of it not working with WiFi enabled on some phones. If APN settings don't help, have you tried turning WiFi off?

No, I don't have any such issues