1) Are the people you're sending to with the problems on the same network? Which network?
2) Have you tried popping your SIM in your old phone to see if it still happens?
3) Does it happen at any time in particular more often?
4) Does sending to people on other carriers produce the same results?
5) Do the recipients have problems with other people on T-Mobile?
6) Do your texts actually get labeled as "sent" in your messaging app, or are they sitting in "sending"?
7) Are you using the default Messaging app? If not, does the same happen when you do?
My guess is it's a problem with the receiving carrier. Unless it's an app that's causing your texts to not go out on time (#6 generally would answer that question. If they get stuck sending, either you have a poor TMobile connection or an app is interfering with sending; factory reset would probably be required and install 1-2 apps a day until you find the problem app)
Smply, thanks for the reply. Let me answer these questions for you.
1. The two people who confirm not receiving my messages are on At&t as well as TMobile.
2. My old phone is not a smart phone. I know all my messages went through on my old phone.
3. I cant say it happens at any particular time, just at random. Sometimes they work, sometimes they dont.
4. Its not dependant on carriers, as you can see from answer 1, its the same across a few carriers.
5. The recipients have not told me of any other problems with other people sending them messages.
6. All of the text I send, get labeled as "sent" on my side, with the correct time stamp.
7. Yes, using default messaging app.
Thank you again for your time.
The only thing that I could imagine is you have too many messages stored on your phone. Although, the only impact I've ever heard with that is it wouldn't send at all. You're saying your stuff is being labeled as sent.
Either that, or an app is causing some weird interference.
I hate to say it, but there are two things to attempt to resolve this. Neither are "happy"
Before I suggest doing any of them, let me suggest you install and configure SMS Backup+. Once it says you have backed up all your texts, we can continue (my suggestions will cause your texts to go bye-bye... This will get them backed up to GMail. Awesome app in the future if you set it to automagically back up, you'll never lose a text message again! And you can keep your Messaging app clean)
Clear Data & Cache on your messaging app. This will delete ALL your text messages on your phone. If you have way too many texts (I don't know where the "things go wonky" limit is, but general concensus is keep <100/thread, <500 total, and <20MMS/thread <50MMS total). You can also try just deleting yourself threads you don't need instead
Factory Reset your phone if it still happens when you don't have many texts on your device. Don't have it restore any apps. If it doesn't happen with a purely clean phone then it's an app. Install 1-2 apps/day, keep track of what you install, and you should be able to narrow down the culprit once it starts happening. Of course, if it still happens with a clean phone, it could be the phone, it could be the network, it could be something in the path from point a to point b. It starts to become trying other things to narrow down if it's the phone or the path.
There's also options 3 & 4 which are the same as above, but on the recipient's phone
I really appreciate your input, and I do agree, it is weird. I honestly only have about 4 apps installed, that I downloaded myself, and this problem was there even before I put any apps on the phone. It also occured right after a I did a factory reset, after I updated to ICS. I always clear my text messages, so there are never any messages left on my phone. I will keep a closer eye on and see if I can pinpoint the problem. Again, thank you for your input.