Exchange free busy cross forest

The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel.
OK, so we have an coquines et calines Autodiscover issue, but people are not complaining about Autodiscover not working as expected.
M Mailbox User smtp.If Exchange On-Premises Exchange Online Free/Busy is failing for all users, you would first check Intra Organization Connector or the Organization Relationship from on-premises.Example: m You can find the domains name by cross-checking On-Premises' TargetAutodiscoverEPR - This should be the address of the On-Premises Autodiscover Endpoint.Example: m TargetAutodiscoverEpr - This should be a valid Exchange Online Autodiscover endpoint.Assuming we would have an Exchange 2010-only environment in the on-premises and weve ran HCW successfully, we should expect to see both an Organization Relationship as well as a Federation Trust which combined is the second option from step #3.Run the below cmdlet in exchange -Identity EWS (Default Web Site) -mrsproxyEnabled true -mrsproxyMaxConnections.In untrusted forests, it isn't possible to control the level of free/busy information that's returned on a per-user basis.Read about this change in our blog post.Run the following cmd Foreach (User in Users) 1 identity User -RemoteForestDomainController Source Domain Controller fqdn -RemoteForestCredential Rcred -LinkedMailUser -TargetMailUserOU DN of new user.Accepted domain and email address policy is configured.1 identity User -RemoteForestDomainController Source Domain Controller fqdn -RemoteForestCredential Rcred -TargetMailUserOU DN of new user OU OR Creating Linked objects for the Resource Forest configuration.
Local browse the SCP and the EWS InternalUrl of the target forest (nwtraders.

ObjectCategory : objectClass : top, msExchFedSharingRelationship, whenChanged : 1/30/2017 1:29:18.