Missing Session Hash

[Billy Weisgerber]

I have an integration mapping setup waiting for a message from Salesforce that then looks up other details from Salesforce then inputs data into a CSV on a server for use and reference. Recently, we have started receiving an error message:

"INVALID_SESSION_ID: Invalid Session ID found in SessionHeader: Illegal Session. Session not found, missing session hash: Pg5DlXO4HSSgA7U+g8Ore6LO69NTlHgjn5Ul2TukvGg= This error usually occurs after a session expires or a user logs out. Decoder: DataInDbSessionKeyDecoder SOQL....."

I have tried updating credentials, resetting the metadata and managing the overall integration mapping, but to no avail, I have not resolved the mapping. Has anybody else experienced this, or am I missing something