Sales Tax code must be entered if the account is a Sales Tax account in Dynamics 365 F&O

I was getting the below error while trying to post a vendor invoice with the sales tax.

Sales Tax code must be entered if the account is a Sales Tax account

Reason: Sales tax code is required when you post a transaction with sales tax group.

Solution 1: 

Go to persolization and add "sales tax code" to the vendor invoice lines screen and select the tax code. Most of the case it should be same as the sales tax group. Then, post the invoice.

Solution 2:

You may also see this error when you are using a sales tax type ledger account in the GL entry and trying to make an adjust/reversal.

To allow/post the entry you will need to disable the sales tax validation on the ledger account which you are tying to make an adjustment

Go to GL -> Chart of account -> accounts -> main accounts

Filter the ledger account -> Posting validation -> And change the sales tax to blank

Now, you can post the GL entry.   After posting the journal entry, remember to change back the configuration to the “Sales tax” in the posting type field.

For more details : https://support.rocksolid.com/hc/en-us/articles/360045430451-D365-Error-sales-tax-code-must-be-entered-if-account-number-is-a-sales-tax-account