I would suggest an FQDN instead of IP address for the external file reference and make sure you have DNS support for IPv6 (usually a AAAA record). SSL at that point is also a good Idea. No Guarantee that this will fix the problem but eliminates a possible cause.
Thanks for reply
Did try the FQDN options - but have not looked closely at SSL. Since migrating to Cloud did have some issues initially. Will try and report back!
Did you try an IPv6 address?
Sorted out the SSL and got further along in connection - but now get an Error 100 message
As I understand - it is a 'file missing' message' which again leaves me wondering why FilemakerGo sees the file and Filemaker SDK does not.
When I turned Error Capture off - Error Message "The host does not support this version of FileMaker"