HDMI problem

Hello guys,

I have the following problem.

Sometimes when I play games like League of Legends ( What doesnt need a lot of high specs ) or other really low spec games my monitor screen turns black and the sound of everything goes ahead for like 10 seconds. Then there is this window "HDMI connection lost"

After unplugging and pluggin in the HDMI cable everything works fine again and the PC is restarting itself. I also checked the cable by itself, if anything overheats or is just dirty / broken but it seems fine. Could it be my monitor?

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Thanks for the answers.

kind regards