Here is the weird story!
We have 2 new imacs and 2 new macbookpro they are pre installed with MacOs Sierra latest version. I installed in one imac Filemaker Server 16 and in the same imac the other imac and the 2 macbookpro filemaker pro client.
From the two laptops I can connect to the hosted database but from the 2 imacs I cannot.
Another macbookpro with filemaker pro advanced connects also fine.
I upgraded the other imac to macos high sierra still the same.
So 3 macbook pros 1 with MacOS High Sierra 2 with Sierra connect fine 2 imac 1 with Sierra 1 with Macos High Sierra dont connect.
The only thing that I notice to be different is that in the laptops it warned me about connecting to a non ssl database and I accepted in the imacs it doesnt pop a message to select that is ok.
If anyone can help....