Product and version
FileMaker Pro 16.0.2
FileMaker Server 14.0.4
OS and version
OS X 10.11.6
tested on iMac 27'' + MacBook Pro
If the fmurlscript extended privilege is non enabled for your account, and if the hosted file is accessed over internet, for instance using a domain name, an opening script (OnFirstWindowOpen script trigger) running an Import Records step that target the current file can fail definitely.
When it occurs, the Import Records step is displaying an additional login dialog, but since it appear to be a secutity problem, if you try to reuse the current account to complete the operation you will get a 803 error. And if the Capture error is Off, a strange message is displayed, saying that the file is already open and you have to try with Open Remote command :
In conculsion, you have no other choice except to cancel the login dialog and obviously, there is no record created.
Then, if the script is resuming and try to go to another Layout, a 18 error occurs "the client have to give the account data to continue" and also the target layout cannot be reached.
Then, unpredictable results can occur.
If you try again to connect to the same file but with a FileMaker Pro 15 version or prior, the issue does not occurs.
If you try again with FMP 16 but using a local IP adress as the host, the issue does not occurs.
The solution for me was to activate the fmurlscript extended privilege for the given account.
But then, the strange thing is i am now unable to replicate the issue again, even if i deactivate the same extended privilege !!!
How to replicate
Upload the attached sample file on a server
Access the Host over the internet using a domain name
Try to open the sample file using 'Admin' account and '1234' password
You should get (if the bug is occurring) a second login dialog that you cannot satisfy.
Activate the fmurlscript extended privilege for the given account
I cannot confirm if it can be due to the different version of the FileMaker Server (14) and the FileMaker Pro (16).