card fall off the bus

I have a CentOS 7.4 configuration with a geforce 560 board.
It happens frequently that at cold start the X freezes and the message is that the NVIDIA card falled off the bus.
I have managed to run the bug report, how can I attach it here?
nvidia-bug-report.log.gz (157 KB)

Opening the case the board seems quite hot and after rebooting the nvidia-smi showed 58°C going down, now 44°C.
Could be a malfunctioning fan in the board that make it overheat at start-up?
Thanks

How can you be so blind?!
Do you not see the scuff marks and signs of struggle?!

Yes gentlemen. This is no accident. This card did not “fall off the bus”. I believe this card was pushed!

xxx.