Changing a certificate from earlier wildcard to specific host

Please see an error when clients attempt to upload images to the endpoint https://prod.example.net.au:9433/

I am not sure it is related but we had renewed the SSL certificate and changed from a wild card SSL certificate *.example.net.au to prod.example.net.au It may be at the client end also...
Would you advise where the problem may be?

One of client Message when trasferring images to us:

24/01/2019 8:01 PM Error Unable to upload images after 3 attempts. System.ServiceModel.CommunicationException: An error occurred while making the HTTP request to https://prod.example.net.au:9433/. This could be due to the fact that the server certificate is not configured properly with HTTP.SYS in the HTTPS case.
This could also be caused by a mismatch of the security binding between the client and the server.

---> System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a send.  
---> System.IO.IOException: Authentication failed because the remote party has closed the transport stream. 
at System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest) 
at System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest) 
at System.Net.Security.SslState.CheckCompletionBeforeNextReceive(ProtocolToken message, AsyncProtocolRequest asyncRequest)  
at System.Net.Security.SslState.ForceAuthentication(Boole