Diagnosis
The online document splitting is active in your system. Here, each document is assigned to a accounting transaction variant and each document row to an item category.You determine for each business transaction variant which item categories can or must be posted here.
A splitting rule is defined for each business transaction variant, which determines which item categories are to be split and how the splitting should be determined.
Additional rows need to be created in a G/L account that was defined in the account determination in an account determination key.
The following error occurred for the document you entered:
No account has been entered for account determination key 000 in the chart of accounts SAPF.
System Response
The document cannot be posted.
Procedure
Enter an account in the account determination
SOLUTION:
STEP 1: Follow the below path and Click on Define Zero-Balance Clearing Account

STEP 2: Select Account Key 000 > Click on Accounts

STEP 3: Create/Copy the Zero Balance Clearing GL Account

STEP 4: Click on "New Entries" and provide the GL Account Number > SAVE.

Thanks,
Adharsh KS