Error while checking suitability of domain controller.....LDAP Server is unavailable.....but it is available!

We are running version 7.5.3.17 and when we use the web interface to manage regular AD related attributes it works great with no errors. However if i try to modify something exchange related like email addresses i get the error message below. The error mentions the domain controller being unavailable but this is not true...

when i open the ds.log file i see the message below.

[2023-01-23T12:51:18.012] [0xF44]: [Error] [PowerShellCommandsProcessor::ProcessPowerShellCommand] An Active Directory error 0x51 occurred when trying to check the suitability of server 'MyDomainController.domain.com'. Error: 'Active directory response: The LDAP server is unavailable.'
[2023-01-23T12:51:18.043] [0xF44]: [Error] (severity=Minor) ActiveRoles.Service.ArsException: An Active Directory error 0x51 occurred when trying to check the suitability of server 'MyDomainController.domain.com'. Error: 'Active directory response: The LDAP server is unavailable.'
at ActiveRoles.Service.ExchangeManagement.GeneralPageAttributesPolicy.OnPostGetAttributes(RequestContext context, GetAttributesRequest request)
at ActiveRoles.Service.RequestPrePostProcessorBase.PostProcessRequest(RequestContext context)
at ActiveRoles.Service.StaticPolicyList.ProcessRequest(RequestContext context, String handler)

The domain controllers are all globalcataloog servers and all available and active and accessible so i dont think this is domain controller related.

I also checked port access to the exchange servers and see that open also so ii am not sure why this is showing an error.

I opened a case with support and they just blame the DC.....