Dear forum

I have a 2-month old Xperia XZ2 Compact.

I have had this issue 3-4 times in the past month, with both regular calls and Skype calls: 

I see the incoming call, the "answer" button appears on the screen, but the screen is not responsive. I cannot answer the call, or do anything else. The caller after a while hangs up, the screen continues to be unresponsive. 

I then switch off the screen, switch it on again by fingerprint or PIN, and all works well. 

This is a serious issue, as I miss calls!

Any suggestions?

Thanks in advance