Exchange migration failing

Hi All

Hope everyone is well. Please can someone assist me with the issue below.

I am trying to migrate a mailbox from on-prem to Exo.

The migration is failing with the following error.

The call to 'https://webmail.mycomp.co.za/EWS/mrsproxy.svc' failed. Error details: Could not establish secure channel for SSL/TLS with authority 'webmail.mycomp.co.za'. --> The request was aborted: Could not create SSL/TLS secure channel.

When I try to validate the migration endpoint in Exo it states that it cannot connect to webmail.mycomp.co.za.

It used to work but just stopped all of a sudden.

Also tried running this:

Test-MigrationServerAvailability -Endpoint webmail.mycomp.co.za

RunspaceId : eb52a2c2-2720-4e94-8b19-2cd6278a218e
Result : Failed
Message : The connection to the server 'webmail.mycomp.co.za' could not be completed.
SupportsCutover : False
ErrorDetail : Microsoft.Exchange.Migration.MigrationServerConnectionFailedException: The connection to the server 'webmail.mycomp.co.za' could not be completed. --->
Microsoft.Exchange.MailboxReplicationService.MRSRemoteTransientException: The call to 'https://webmail.mycomp.co.za/EWS/mrsproxy.svc' failed. Error details: Could not establish secure channel for SSL/TLS with authority
'webmail.mycomp.co.za'. --> The request was aborted: Could not create SSL/TLS secure channel.. ---> Microsoft.Exchange.MailboxReplicationService.MRSRemotePermanentException: Could not establish secure channel for
SSL/TLS with authority 'webmail.mycomp.co.za'. ---> Microsoft.Exchange.MailboxReplicationService.MRSRemotePermanentException: The request was aborted: Could not create SSL/TLS secure channel.
--- End of inner exception stack trace ---
--- End of inner exception stack trace ---
at Microsoft.Exchange.MailboxReplicationService.MailboxReplicationServiceFault.ReconstructAndThrow(String serverName, VersionInformation serverVersion)
at Microsoft.Exchange.Connections.Common.WcfClientWithFaultHandling`2.<>c__DisplayClass4_0.<CallService>b__0()
at Microsoft.Exchange.Net.WcfClientBase`1.CallService(Action serviceCall, String context)
at Microsoft.Exchange.Connections.Common.WcfClientWithFaultHandling`2.CallService(Action serviceCall, String context)
at Microsoft.Exchange.MailboxReplicationService.WcfClientWithVersion`2.CallService(Action serviceCall, String context)
at Microsoft.Exchange.Migration.MigrationExchangeProxyRpcClient.CanConnectToMrsProxy(Fqdn serverName, Guid mbxGuid, NetworkCredential credentials, LocalizedException& error)
--- End of inner exception stack trace ---
at Microsoft.Exchange.Migration.MigrationEndpointVerifier.VerifyConnectivity(MigrationEndpointBase endpoint)
at Microsoft.Exchange.Management.Migration.MigrationService.Endpoint.TestMigrationServerAvailability.InternalProcessEndpoint(Boolean fromAutoDiscover)
TestedEndpoint :
IsValid : True
Identity :
ObjectState : New

Appreciate any advice and feedback.