We had a similar issue in our project where CDC is set up on Oracle table. Everything was good-- table added to CDC , Register Subscribers, Start Journal and I can see all the sessions successful in Operator. Logical Physical pair is set up properly for that Context. I go same error message.
When I check the set up in Topology for that Physical schema, it's Data Schema and Work schema are given in Small letters. For example, if we take HR schema, it is given as hr . I changed it to capital letters HR and everything worked fine.
The only reason I could think of was , when ODI tries to communicate with DB, its trying to do with double quotes like "hr".
I know this is very old post, but I just wanted to share solution which worked for me.