Time?

Because both based on certificates. Certificates need to have time synced between each other, otherwise they could be invalid, not valid or other checks could be corrupt. 

Certificates and time is one of the oldest issues with IT. 

But I thave the same time in both server and client. And certificate time pass into accepted range. Have you tested this?

But I thave the same time in both server and client. And certificate time pass into accepted range. Have you tested this?

You asked about, why it could potentially not work with incorrect time. It is because of certificates and how they work. 

If you time is correct on both devices, it should work. 

How much time can be different? And how it knows what is correct time? I have turned NTP off.

I already told - times are sync only not todays time.