Recently when working on a migration for a client I ran into an error in ODI I had seen before but forgot about. This one was "ODI-26016: The requested operation cannot succeed. The object no longer exists." in the detail of the error I found the text "SnpPschema does not exist".
I ran a quick google search and found the following forum post. While this post didn't get me to the exact answer it provided a lot of insight and jogged my memory. I figured I would write this down so next time I be able to resolve it even faster.
Anyway what had happened is one of the other ODI users had recently deleted one of the contexts. Normally not a big deal but as luck would have it this particular context was used as the optimization context instead of for just about every interface in our repository. When this happens the optimization context gets set to
Apparently ODI requires an optimization context to be defined even if its not being used. Once I set the context to something that still existed (Global) the interface worked as expected.