Hi there,
Firstly, the MMS documentation here appears to be incorrect:
https://www.3cx.com/docs/supported-sip-trunk-requirements/#h.9lv8vi548lbk
The SMS documentation has the from/to/text inside a payload element, but the MMS documentation does not.
I implemented my initial POST to the 3CX...
We are excited that MMS is supported on 3CX V18! We have been testing MMS and have come across the following issues. We are hopeful that 3CX can take action quickly so that the MMS service is sellable and usable.
Image/file size when sending photos
The majority of carriers don't accept images...