Opening a shared databases remotely using a URL is described on this help page:
Per those instructions, you can include the user name and password like so:
However, this technique fails if the account being logged into is required to change its password on log in. In that case, FileMaker behaves the same as if an incorrect password was entered in the fmp URL. That is to say, it challenges the user to Provide the user name and password.
Thank you for your post.
I am able to replicate the issue under macOS Sierra 10.12 and Windows 7. I have sent your post along with my findings and a sample file to our Development and Testing departments for review. When I receive any feedback, I will let you know.