My wife just sent a group text and when I replied she didn't get my message but just a text from "Unknown"
I usually keep my data connection off and only turn it on when I need it like getting group texts. When I sent my reply to her I then went and turned off cell data. I thought maybe turning off data too quick was the culprit but I sent a second message and left data on but she just got the "Unknown" message.
I'm also on AT&T but with an L920. Wonder if AT&T is having a problem.
I know it's not on WP8 but it is possible AT&T may be having issues. I have an Iphone and over the last few days texts have been coming up as "Failed to send" on my phone and family phones as well. Additionally some messages are displaying from blank contacts.
I don't think that's an AT&T issue since I got the same message once and I'm living in France. I have a Nokia Lumia 925 btw. I wonder what it was though.
Moved lumia 822 (win10 build 10.0.10581.0) from USA Verizon to AT&T. Now getting this issue, unknown - message not found. Very annoying. Hopefully the new Lumia 950 I'll get on AT&T doesn't have this issue.