How to fix error Error: CommunicationErrorTransientException:Could not establish trust relationship for the SSL/TLS secure channel with authority

Paulina Lukas 0 Reputation points
2025-02-21T13:03:24.82+00:00

we are running a ybrid environment , we create user mailboxes on our on prem exchange and than migrate the mailbox to exchange online , we have been doing that succesfully up until last week , when it started fsiling for all mailboxes , it stay for the whole day on sync and says completed with below error . the mailbox fails to migrate .

Error: CommunicationErrorTransientException: The call to 'https://owa.mtc.com.na/EWS/mrsproxy.svc' failed. Error details: Could not establish trust relationship for the SSL/TLS secure channel with authority 'owa.mtc.com.na'. --> The SSL connection could not be established, see inner exception. --> The remote certificate was rejected by the provided RemoteCertificateValidationCallback.. --> Could not establish trust relationship for the SSL/TLS secure channel with authority 'owa.mtc.com.na'. --> The SSL connection could not be established, see inner exception. --> The remote certificate was rejected by the provided RemoteCertificateValidationCallback.

Microsoft Exchange Hybrid Management
Microsoft Exchange Hybrid Management
Microsoft Exchange: Microsoft messaging and collaboration software.Hybrid Management: Organizing, handling, directing or controlling hybrid deployments.
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