2021 Estimated Tax payment to the IRS

Has anyone living in the UK used the IRS direct pay system to make an estimated tax payment?  I tried to do it today but could not get it to verify my identity despite filling in the information requested from my 2020 return.   I suspect that it was having trouble with the postcode.  In the end I resorted to paying via a debit card on the payUSAtax website (one of the other payment options on the IRS site) rather than a direct transfer from my US bank account.  It cost me about $3 and won't show up at the IRS for 5-7 days but it worked OK. 

Yes, I pay online using the IRS electronic fund transfer, but I had been doing so for many years so had it set up long before we moved back.