Op, if your using a wireless keyboard, check it's working right, bats ok ?
Try creating a new link to the bank log in, don't use a save bookmark.
Both these have tripped me up in the past, with Santander.
Never had to use main branch for this.
Changed passport number yellow bank in nongkhai, account in pattaya.
changed, passport number Bangkok bank nongkhai, account in pattaya.
No problem at all.
All done in about 15 minutes.