Problem Receiving Calls

[Braddington]

Hello everyone,

I own an Xperia TL and am finding that not all calls I receive are actually being received. This is my third Xperia TL and I had this same problem on my two previous Xperia TLs. Sometimes I receive a call but the telephone doesn't ring and the screen doesn't go to the incoming call screen. However, whoever is calling can leave a voicemail. I don't understand what could be causing the problem. I am not connected to any bluetooth device when this error occurs. Additionally, I performed a software repair and it didn't make a change. I think is a glitch on Android 4.1.2 but I am stuck on Android 4.1.2 since AT&T will never release an update to Android 4.3. I also cannot go down the flash route since I will void my warranty and I need the warranty. I don't know of any app I could reset to fix this either. Does anyone have a solution to this? 

I forgot to add that I have also checked my call barring (blocking for U.S. English mode) settings and they are all disabled so anyone can call me. I do not have a third party app installed that barrs calls either. 

[Uliwooly]

AT&T is terrible, you can manually update and still keep LTE 

http://talk.sonymobile.com/t5/Xperia-S-SL-acro-S/How-to-manually-update-root-downgrade-2012-Xperias/...

[Uliwooly]

Also it doesn't hurt to get a brand new micro SIM card, just walk into any AT&T store and tell them that it stopped working, they won't charge you at all 

[Braddington]

I wanted to go down that route but my warranty will be voided and I really need the warranty since my last two Xperia TLs both had hardware failures and I don't have the funds to move to a new different model smartphone such as the Z1 C6906 model I have my eye on. 

[Braddington]

I will try the micro sim card suggestion. I am near a corporate store that gives out new SIM cards for free. The non corporate store charges me $15 for a SIM card. 

[Uliwooly]

Well you won't quite lose your warranty, you can create a backup of your current fimware

[Braddington]

I was able to retrieve a new SIM card and installed it so I will wait and see if this problem occurs again. I am hoping it won't but I fear that it is most likely a software glitch. The only aspect I miss of the iPhone is how updates can be installed right after they are released and the software is quite stable yet not perfect. I don't think I have ever used perfect software.