I am unable to send or receive MMS since porting my number back to Optus from Telstra.
I can make and receive calls, send and receive sms, and use the net. Coverage is good. I am using a Blackberry 9700 and yes it still works well and I don't want to change the device yet. We have reset network settings, checked APN settings with Optus support, and factory reset phone, but still have the same issue.
Blast from the past with this one.
Click the settings icon
Click the options icon
Make sure "multimedia reception" is set to always
Make sure "Automatic retrieval" is also set to always
Pretty sure also best to check the read/delivery as on.
Besides the apn details for mms thats the only other place i remember that could impact mms.
I have exactly the same problem on my wife's HTC U11 Eyes (Android 7.1.2)
MMS messages to Telstra/VF (at least) have stopped working, but phone reports as message sent.
Also having trouble receiving MMS messages from Telstra/VF (at least).
Don't know about sending and receiving to Optus phones - we don't have any besides this one (and that might change, too)
Converting text messages to MMS when too long doesn't help matters, either.
The first thing to try if you haven't already is putting your wife's SIM in another phone to determine if it's a problem with the network or the phone itself.
If it doesn't work when in another phone, next step from there would be to contact Optus.
If it works in another phone but not the HTC, you then know it's an issue with the phone.