GL_ADFDI_UPL_ER_NO_LEDGER: The ledger is invalid for your current data access set

Hi Guys

Please can you help, I am getting this error intermittently:

GL_ADFDI_UPL_ER_NO_LEDGER: The ledger is invalid for your current data access set

I need to set up and run the AutoPost scheduled tasks on 2 different ledgers, scheduled to run every 15 mins during the day by our "system user" which has data access to both ledgers.

I had this error last week, and thought I had solved it by logging in as the user, selecting the relevant ledger and scheduling each AutoPost to run when in the ledger, but this morning the same error happened again.