How do I fix the Schannel error?

I am getting multiple errors everyday on the exchange servers:

System Log:

Level      Date and Time                      Source             Event ID           Task Category
Error      2/20/2018 2:22/46 PM         Schannel         36888               None

General:

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 20. The Windows SChannel error state is 960.

 

  - Provider

   [ Name]  Schannel
   [ Guid]  {1F678132-5938-4686-9FDC-C8FF68F15C85}
 
   EventID 36888
 
   Version 0
 
   Level 2
 
   Task 0
 
   Opcode 0
 
   Keywords 0x8000000000000000
 
  - TimeCreated

   [ SystemTime]  2018-02-20T20:22:46.249907500Z
 
   EventRecordID 343687
 
   Correlation
 
  - Execution

   [ ProcessID]  596
   [ ThreadID]  8728
 
   Channel System
 
   Computer exchg1.mydomain.net
 
  - Security

   [ UserID]  S-1-5-18
 

- EventData

  AlertDesc 20
  ErrorState 960
jesus ramirezAsked:
Who is Participating?
 
RobertConnect With a Mentor System AdminCommented:
If you look in the following article error 20 indicates a bad mac record.
https://blogs.msdn.microsoft.com/kaushal/2012/10/05/ssltls-alert-protocol-the-alert-codes/

Schannel is very chatty in the logs and will report just about any issue.

There is a registry settings you can adjust to change what is logged and you can use that information to help track down the problem.
IE:
HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\Schannel
 Value Name: EventLogging
 Value Type: REG_DWORD
 Value Data: 7

Anyway for your reference this is a similar report of this error.
https://www.experts-exchange.com/questions/27957073/Active-Directory-Certificate-Service-Schannel-Errors-Event-ID-36888.html

If you recently changed any certs I would start there.
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Adam BrownConnect With a Mentor Sr Solutions ArchitectCommented:
For this situation, TLS reporting error 20 usually means that a network communication error occurred. This is *usually* just a matter of one bit being incorrect or the message was corrupted in transit. Unless the error occurs a lot (and by a lot I mean once or twice per minute or more) it usually isn't something you can either replicate or fix, so don't worry about it. If it *is* happening a lot, you would need to run a wireshark capture to examine the SSL/TLS exchange to see what is breaking.
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jesus ramirezAuthor Commented:
OK, I do seem quite a bit of them but we also do have many mobile users that report frequent email issues usually caused by lack of a strong signal to the phones or tablets being used.
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Adam BrownSr Solutions ArchitectCommented:
That would likely be your cause. Signal disruption would absolutely cause this error because it would fragment data packets and result in bad mac errors when initiating SSL connections.
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Seth SimmonsSr. Systems AdministratorCommented:
No comment has been added to this question in more than 21 days, so it is now classified as abandoned.

I have recommended this question be closed as follows:

Split:
-- Robert (https:#a42475703)
-- Adam Brown (https:#a42475729)


If you feel this question should be closed differently, post an objection and the moderators will review all objections and close it as they feel fit. If no one objects, this question will be closed automatically the way described above.

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