I dealt with a support issue for a client recently where they were reporting that one user could integrate into all but two companies in Microsoft Dynamics GP, but other users couldn’t integrate into any.
The problem is that when they tried an integration which failed, SmartConnect simply crashed with nothing in any error logs in either SmartConnect or Windows.
As it was working in some databases and not others for one user and not at all for other users, it had to be permissions. The user who could use SmartConnect was the one involved in the implementation and the companies he could use it in were the oldest; the two companies which failed were the newest.
We did some checking and found that the user who could run some integrations had his domain account created as a SQL login and had been granted the DYNGRP security role on the company databases; he had not been added to the companies which failed. When we added the security for these databases the integration ran successfully.
We recommended to the client that instead of adding individual users to SQL Server and giving them access to databases they consider creating some AD security groups which had access assigned and they could then grant those roles to users as required.