First steps for troubleshooting EDI issues in Acquisitions?

Product: Voyager
Product Version: All
Relevant for Installation Type: Multi-Tenant Direct, Dedicated-Direct, Local, TotalCare

What are first steps / initial information to gather to troubleshoot an EDI issue?

Find answers to following set of questions:

Is issue with outgoing (sending messages; Serial Claim or Purchase Order) or incoming (loading messages; Invoices or Serial Claim Responses) messages?
What is EDI Connection Profile used?
Where is message file on server (file name and path)?
Has file name been used before (non-unique)? Voyager will not allow processing of filenames used previously.
Is file name greater than 30 characters? Prior to 10.3, Voyager will not allow processing of filenames exceeding 30 characters (file won't show up in "Receive a File").
Can issue be replicated?
What message does client give?
Are you certain the vendor is certified? See below for more information.