mobile data turns off and turns on randomly

[martin1984]

For last one week, mobile data on my Sony Experia Z turns off and then turns at least 50 x times a day. I just shuts down, little x sign i showed next to the signal sign, and then after one minute or so, turns on again. Also, mobile data is set on h+, altrough I have LTE subscription, and only brief period of time it reaches 3G.

What's the problem.

[Uliwooly]

it could be 

1. poor network coverage
2. wrong APN settings
3. you need a new SIM card 
4. an intrusive app could cause this (taskillers, task managers, antivirus, etc)

[cfernandezr]

uliwooly, I have the same issue and I have verified the 4 possible causes you said, and it remains the same. Any other suggestion?

[JakeSully]

reason why you get x next to signal bar is because it cannot recive signal to any of carrier towers near by.