SQL 'sa' user cannot login to Dynamics GP 2015

Every now and again I see a post in the Dynamics GP community forum which tickles my fancy. Most recently, a forum user reported the following issue:

I have a new install of Dynamics GP 2015 in a terminal server environment, installed on SQL Server 2012 using SQL Server Authentication.  The 'sa' login works fine when launching SQL Management Studio but when attempting to login to GP I receive the following:

All other users can log in including DYNSA.  In addition, I'm not able to add companies in the new install of Management Reporter which I assume is related.

I was impressed when Jorge Mejia asked one question about logging into GP Utilities and the length of the 'sa' account's password.

There is a mismatch between the ‘keyable’ length for the login password between Dynamics GP Utilities login and Dynamics GP login windows.

The maximum length of the datatype for the password in the Dynamics GP Utilities login window is 30, while the maximum length of the datatype for the password in the Dynamics GP login window is 15, therefore you have to go for the shortest length.

Symptoms:

Cannot Log Into Dynamics GP using SQL Authentication

Can Log Into SQL Server Management Studio

Can Log Into Dynamics GP Utilities

Cannot Add New Company/Companies in Management Reporter

Diagnosis:

SQL 'sa' account password longer than 15 Characters

Resolution:

Change SQL 'sa' password less than 16 characters long.