I have been trying to get my unlocked Blu Advance A6 on Android 7.0 working with Project Fi and I can't seem to get MMS messages working in the default app or Signal.
Regular text messages can be sent and received OK, but when an MMS comes in it just says "Tap to download" and when I try to send one it says "Not sent. Tap to try again."
I thought that maybe it was due to the APN settings being incorrect but the Access point names menu that is supposed to be located in Settings -> Wireless & Networks -> More -> Cellular networks is missing. There is only a toggle for Data roaming and no other items.