@cantaccessaccount
This is a tax website, (NOT quickbooks either) and is not linked to the US Govt in any way.
Not sure anyone here has any insight on CSRS email changes/linkages/ setups with their new system and how it is best done. (not sure what you think it has to do with quickbooks either)
The Quickbooks community is waaaaay over here (link below). Ask over there, with some more details and maybe someone there will have a clue as to how you need to proceed:
US QuickBooks Community (intuit.com)
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If the issue is that you can't get your CSRS account linked and setup for the new login.gov system, with the proper same-email, you will need to actually call CSRS/OPM, and ask an agent for help on the phone.
There's a "Call Us" phone link on this page, but I can't be sure it is exactly what you might need:
(scroll waaay down the page)
What is Login.gov? (opm.gov)
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
