#1: None of those issues you mentioned apply. I had no problems paying via ACH from my business bank account, and then suddenly I couldn't - declined, declined, declined, declined.   The payments are relatively the same amounts on each invoice and there were more than enough funds in my business account to cover them; the account and routing numbers did not change, and the payments in question went through just fine from my personal account at the same bank. This is, of course, starts an accounting issue for me to deal with.  I bank with the most well-known Bank in America and have had no problems making payments on non-QB ACH invoices from my business account.  :|

#2: I received NO EMAILS FROM QUICKBOOKS as to why the payments were declined.   I had to reach out to my vendor to confirm there was no issue on their side, and there was not.  I am not interested in setting up multiple payment methods because QB has a glitch that they can't fix.