Salesforce Sync Error: Invalid Session ID Found in Session Header: Illegal Session

[gabby_]

When attempting to sync a new lead from Marketo into Salesforce we get the following error:

Sfdc lead retrieve failed: Invalid Session ID Found in Session Header: Illegal Session

I opened a ticket with Marketo support and they suggested creating a brand new sync user in Salesforce, which I did however we are still getting the same error. Everything else is syncing fine, though. It only happens when the lead is new and doesnt already exist in salesforce.

Does anyone have experience with this issue? It seems as if the problem originates from the Salesforce side.

[Tara_Dacci · Accepted solution]

Hello @gabby_ 

I keep a log of sync errors but haven't personally seen this one before. I did however find a thread in the SF community with a couple of possible causes. If you were on a VPN it could have been caused by the VPN changing IP addresses. If that's the case they recommend updating your Session settings by unchecking the "Lock Sessions to the domain in which they were first used".

Sounds like it was a result of being accidentally logged out during the sync.  Check out the full thread here. 

https://developer.salesforce.com/forums/?id=9060G000000BiXQQA0