Android 7.1 error

Hi guys,
what do you make of this?
“Method:XdsBase.Message:E=class javax.net.ssl.SSLHandshakeException/Unacceptable certificate:CN=Let’s Encrypt Authority X3, 0=Let’s Encrypt, C=US.”

I have tried to connect this device to my CMS 1.8.11 with no success. The Android player version was 108.
Looks like player cannot connect to CMS at all.