Lost capability to text: Contacts show sip:[phone number]@msg.pc.tmobile.com;user=phone

I am also having this problem. My daughter and I text my husband and they fail. My son's text to him ARE going through. Started just in group texts, now every text since Thursday (4 days).

Has anyone found a solution yet?? We've been to Tmobile location 3 times now.

We both got phone updates and everything went back to normal for about 2 weeks. Now, messages to her failing again. This is how it started last time. 

I found a quick fix for this strange problem.

apps: Messages-

Defaults: Clear Defaults

Working now as normal and phone number is normal and not Sip….

Having the same issue only to one number. This is very frustrating. Got a message from support nothing found ….WHAT????  So just leave me handing?….  We have 3 people who cannot text to this number. Come on T Mobile……FIX THIS

I also have the texting issue pertaining to "sip:+".  I spent nearly 2 hours on the phone with Tmobile last week with no resolution. They told me they would call me back the next day.   ...still waiting for that callback.   I did, however find a clunky way to text a contact with the issue.   I just text them at:  +1THEIRNUMBER@tmomail.net. It's not a great solution, but at least I can communicate with them.  Considering how much I pay a month, being able to communicate is sort of expected.

I was having the exact same issue.  I called T-Mobile support and talked to three different people, the last one was actually a Samsung Tech (I have a S23).  We figured out that I was using an outdated Messages app (it had the 3 dots on the icon), that had been transferred over from my old S8.  The correct version is the one that has a blue message bubble on the icon.  Hope this helps. 

Same exact issue!  Happened about a week ago.  My husband and I can't text our daughter.  She can text us but comes through with the SIP # and won't let me update her contact.  I've deleted her contact and try to put her back in, but nothing!  Neither of us can text her. It's the only contact we have an issue with.  Seems to be families on the same plan have an issue with one contact on the plan who has a different phone.  This is supper frustrating and needs to be fixed TMobile!  We had sprint and never had an issue like this!

I have also been experiencing this for about the past week, one contact only, my husband. Sometimes it works, sometimes it doesn't....and when he replies to my messages they usually come through as this weird sip crap. What give TMobile? I pay too much for all my lines for this. Sprint never did this to me!

No fix for me using the stock texting app. I ended up installing Textra and I don't have the same texting problems.  Not an ideal solution, but it's a work around until tmobile gets their act together.

Did a fix for this come up? I am having issues texting one contact. Same as other comments.