Hello there! I have a similar problem. I have a FP5 and RCS works with other RCS-users. But, some of my contacts can -sometimes- not receive my messages… iPhone-users.
I can’t receive links or pictures from non-android users. I will start a new thread about this.
“FP5 RCS and IOS and texts”
I’m wondering if it is the settings on the IOS-users phone that are set to strictly iMessage or something?
I moved your comment out of the FP4 topic.
Yes a SIM card used in an Iphone might have issues with messages on Android. You might find hints in general using your search engine of trust or here in the forum there are hints as well.