Sage 50 Canada - Sync Error: Could not allocate line * of invoice **** to a job site because (Account) does not allow job site allocations!

Cause

The account coded to the invoice doesn't not allow job site allocations. 

Resolution

In Sage 50 Canada edit the Account and check Allow Project Allocations. 

The invoice will be in SE status on the Export tab, export the invoice and sync. You should see that the sync was successful.