Why the balancesheet is not balance
That is not your Balance Sheet report. It is your Trial Balance report.
Your complaint seems similar to this one: Unbalanced balance sheet!. If you read that thread, you will see that it was traced to withholding tax via journal entries, which is not how withholding tax is supposed to be entered. Are you using withholding tax (tax withheld at the source)?
Yes, I use withholding tax. Is there a solution to solve it?
The question was
i.e. You should not ever use Journal entries for withholding tax see Manager.io
I think this should be categorized as a bug,
If Withholding Tax accounts are allowed in Journal Entries, their values should appear on the Balance Sheet and Trial Balance Reports.
From this view, Withholding Tax is well recorded in Custom Reports
but the Withholding Tax value does not appear in the Balance Sheet and Trial Balance reports