Exchange 2013 event ID 36888 SChannel error 12 and 1203

I am running Windows Server 2012 STD with Exchange 2013 installed on the same server. I know that Microsoft doesnt recommend to do this, but I had no choice. Errors are follow:
A fatal alert was generated and sent to the remote endpoint. This may result in termination of the connection. The TLS protocol defined fatal error code is 10. The Windows SChannel error state is 12.
A fatal alert was generated and sent to the remote endpoint. This may result in termination of the connection. The TLS protocol defined fatal error code is 10. The Windows SChannel error state is 1203.

-System
-Provider
[ Name]Schannel
[ Guid]{1F678132-5938-4686-9FDC-C8FF68F15C85}
EventID36888
Version0
Level2
Task0
Opcode0
Keywords0x8000000000000000
-TimeCreated
[ SystemTime]2014-11-25T23:30:34.120233400Z
EventRecordID121125
Correlation
-Execution
[ ProcessID]1064
[ ThreadID]20184
ChannelSystem
Computerserver
-Security
[ UserID]S-1-5-18
-EventData
AlertDesc10
ErrorState12
System
-Provider
[ Name]Schannel
[ Guid]{1F678132-5938-4686-9FDC-C8FF68F15C85}
EventID36888
Version0
Level2
Task0
Opcode0
Keywords0x8000000000000000
-TimeCreated
[ SystemTime]2014-11-26T05:45:22.650086300Z
EventRecordID121230
Correlation
-Execution
[ ProcessID]1064
[ ThreadID]45336
ChannelSystem
ComputerSERVER
-Security
[ UserID]S-1-5-18
-EventData
AlertDesc10
ErrorState1203
Process ID 1064 is Isass.exe

I found somewhere that error 1203 could be ignored, but nothing about error 12. 
Server is running with selfsigned SAN certificate, hosted 2 exchange domains (10 mailboxes, 5 local, 5 linked for remote domain connected via external 2 way non transitive domain trust).
Thank you very much for any advise.

Regards,

Jan