One of the reasons for this is an Inactive Tax Control Account.
Please perform the steps below to resolve this:
1. Navigate to Setup > Accounting > Tax Control Accounts. Take note of the active and inactive Tax Accounts
- To show inactive Tax Accounts, Mark the Show Inactives checkbox to show inactive items
2. Navigate to Setup > Accounting > Tax Codes
3. Find the Tax Code with internal ID XXXX mentioned in the error message "…Invalid taxitem reference key XXXX" which is the Default Tax Code setup in Setup > Accounting > Set Up Taxes
- If Internal ID column is not visible, navigate to Home > Set Preferences > General > Show Internal IDs = T
- Mark the Show Inactives checkbox to show inactive items
4. Edit Tax Code with Internal ID XXXX
5. Take note of the set Tax Account
6. You may either select the Tax Account to an active one or go back to step #1 and reactivate Tax Account.
To reactivate Tax Account
1. Navigate to Setup > Accounting > Tax Control Accounts
2. To show inactive Tax Account, mark the Show Inactive checkbox
3. Clear the checkbox of the Tax Account item
4. Click Submit