Thank you for your post.
Do you have the fmrestorelogin extended privilege set for that user account?
From Page 10 of the FileMaker Go 1.2.1 Technical Brief at:
FileMaker Go supports the “fmrestorelogin” extended privilege. To take advantage of this extended privilege, you must create a new extended privilege using “fmrestorelogin” (no quotes) as the specific keyword.
FileMaker Go, by default, will not save the user name and password of a file that is terminated. The next time FileMaker Go is launched, it will prompt the user for their credentials and attempt to restore the user’s prior session, except in the following cases:
• The current user is logged in using a Guest account. FileMaker Go will let the user immediately reconnect as a Guest.
• The current user is logged into a FileMaker database where automatic log in to the file was turned on in the File Options.
• The current user is logged in using an account that is associated with the “fmrestorelogin” extended privilege. This privilege exists to allow users to resume an interrupted FileMaker Go session without being further stalled by an authentication dialog. In these cases it may be prudent to recommend that all users lock their devices using the iOS security code feature.
The “fmrestorelogin” extended privilege works with Auto-Restore Login application setting (Home screen > Settings Menu) in FileMaker Go. If the setting is turned off, a user will always be prompted for their credentials.
If FileMaker Go is closed as a result of a user pressing the Home button or an incoming call, multi-file solutions will not prompt the user for credentials for every file when “awoken.” FileMaker Go simply prompts a user for credentials when opening the first file. As long as the other files in the solution contain the same account and password, no additional credentials prompt will be displayed.
The FileMaker Go client should honor all of a solution’s existing security settings. This means anyone authorized to access a database via FileMaker Pro is similarly authorized to access that same database, with all the same privileges, in FileMaker Go.
Let me know if you need additional clarification.