Adobe acrobat pro 2017 add /modify custom paper size not working

I have been printing to Adobe PDF from within Coreldraw2019 without issue until today. All of a sudden I can no longer add a custom page size, the add/modify button won't add or modify anything. Instead it is deleting already existing custom sizes, which I then can't add back. I tried the same process with Coreldraw 2018 - same problem. So I did a repair on adobe acrobat pro 2017, still doesn't work. Has anybody had this same problem and have a fix? Thanks