Schannel Errors on Exchange 2010 server

D_Batona used Ask the Experts™
The following errors are regularly found in "System" log on Exchange server:

An TLS 1.2 connection request was received from a remote client application, but none of the cipher suites supported by the client application are supported by the server. The SSL connection request has failed.

It is clear they are coming from Active Sync or OWA.

How can I determine who device is causing that?

I checked all logs in TransportRoles\Logs but was not able to find.

Thank you.
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AmitIT Architect
Distinguished Expert 2017

I spent hours with MS for this issue. Finally, I was told to ignore it. looks like MS bug. If it is not causing any issue to your server, I suggest to ignore it. However, if you still want to find root cause, call MS.
Senior IT Consultant
I had the same exact error and I solved it by making two steps.
1- Make sure your Exchange server have 80/443 traffic allowed outbound as it tries to connect to Microsoft's CRL (Certification Revocation List) to verify the certificates of the server is expired or not.

2- Make sure that the public certificate where you're IIS is published has the correct chain ... you need to have the root, Intermediate and personal certificate all in place.

If your exchange server is blocked from accessing Internet for restriction policy then you need to manually download all the CRL certificates and import them on your Exchange Server's CRL store.

The other solution would be to disable the log on the registry. This can be achieved by creating a REG_DWORD called "EventLogging" in the HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\SecurityProviders\SCHANNEL

Make sure you set the eventlogging value to 0 and restart Exchange server for changes to take effect.

If nothing works check this link, it might give any clue although it does look not related.


Yes I see ..

Certificate is causing that.

Thank you!

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