After a payment has been processed and sent to the payment gateway I see the error message 'either you are not logged in, or do not have access to this content'. Despite the error message the transaction is completed successfully.

This has started happening for no apparent reason. I did see a reference to 'User Registration' not set to Public within the Advanced section of the Store Admin but I checked that this was set correctly. I can't figure out what is going on.

Any suggestions??