enter loan payment not workiing

running current version of quicken deluxe on windows 10. when I start the "enter loan payment" for a mortgage account, the amount is auto- entered but greyed-out, so when I try to complete the payment transaction, a zero is entered into the account register. the procedure has worked for many years, and seems to have broken in 2023 (this is the first time I've tried to complete this action, last time was december 2022). anyone else having this issue?