I switched from Verizon to T-Mobile today. Seems like everything went OK except that many of my text messages are sitting there with the loading bubbles and many, many messages are missing. I use Apple messaging. I don’t believe there is any correlation with iMessage vs text messages. I go from this weeks messages to messages from 2020.
iPhone 12 Pro
Hello byrdieep,
Welcome to Apple Support Communities.
We understand that since you switched carriers that you are missing your messages. We are happy to assist.
When you switched carriers, did you get a new phone and restore it from a previous backup? If not, are you using the same phone and just switched the SIM card? Do you use iCloud for Messages? What do you have message history set at i.e. 30 days, 1 year, forever? Please go to Settings > Messages > Message History > Keep Messages. These answers will help us to isolate the cause.
Here’s more information on iCloud for Messages: Set up iCloud for Messages on all your devices - Apple Support
Let us know if you have further questions.
Take care.
Many text messages missing after switching to another carrier sim card
