S2721DGF, buttons not working

Good afternoon,

A few days ago I received a new S2721DGF monitor. Upon switching it on, the OSD menu was open but the panel buttons were not reactive, meaning that at first I could not change the language or even close the menu. After a hard reset of the monitor I was able to set the language and also close the menu, which indicates that the buttons should physically be working. However, since then the buttons seem to have gone back to their non-reactive state and I was not able to open the menu again. I tried several hard resets and also "unlocking" the menu by holding the main button for 20 seconds (in fact I tried that with every button) but it is still not working. Any ideas how to solve this issue?

I'm running the monitor with an Asus RTX3070 connected via DP. The OS is windows 10.

Best wishes,

Jan