On Saturday afternoon, while I was watching videos on YouTube (using mobile data), my SIM 2 suddenly stopped working (like it had been disconnected somehow). I am based on Greece and my SIM 2 is Vodafone GR (Vodafone CU/Prepaid). I talked with a representative I described my problem fully. They said that my connection and my mobile data was fine.  I also told them that I am using a MEIZU m2 (mini). They looked up to find if it was a device problem, but I got no answer. I asked them if a reboot (shut down and boot normally after approx.10 sec) would help. They agreed with me to try this.  I tried so and it worked. This is happening once a day since Saturday. I got the SIM card on 18th of March and until Saturday (almost 1 month) it was working fine. I had the same problem also yesterday and I had to reboot my phone again. It also happened today, but twice. (As I was writing this thread, it disconnected for the second time)
My SIM 1 (Cosmote GR, also prepaid) is working fine, with no issues. Also, both of my SIM cards disconnected from the service providers twice today.  

I think that the problem originated from the CPU, which I think is very close to the SIM tray. It also overheats sometimes. And when the SIM 2 disconnected on Saturday, the CPU was overheating.

Can you please help me with my problem ASAP?