Trusted connections depend on the Windows login used to run the process, and has nothing to do with MAS_Reports. Make sure the Windows account you're using has db_datareader access to the databases you want to access, the DSN has a default database set, and that the instance is properly referenced.
I'm not sure about MSAccess, but know you can copy / paste a working connection string into Excel, which is worth a try.
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Kevin Moyes
Technical Systems Analyst
Munjal White Consulting Co.
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