No Operating units for Party Tax Profiles
The ledgers and OUs are all set up, You have set the MO Security profiles for the tax manager, added the ledger set, done everything possible but for some reason, you cannot select an OU for the tax managers–>party tax profile.
1. Receivables -> Set up -> System -> Organizations.
2. Query the OU used.
3. Check the location tab and the address.
4. See if country and address are populated correctly.
I have blanked out the client info but hopefully you will get the idea