I changed primary bank accounts from Regions to Bank of America and now I can't write online checks
That is true. B of A no longer supports Quicken's Direct Connect, which is required to write online checks from Quicken. You have lost that option.
Thank you very much.
OK thanks.
If your bank (the one that runs your checking account) recently required you to reauthorize your checking account and/or your bank has changed from "Direct Connect" to either "Express Web Connect" or "Express Web Connect+" you can no longer use Online Bill Pay direct to the bank or Quicken Bill Manager's Quick Pay function. The bank no longer supports this function through Quicken.
IMHO, you have these alternatives (in no particular order of preference):
I've been using method #3 for decades, since before the Internet and transaction download capabilities were even introduced. It's easy to get used to this process. And I have yet to miss a single payment.