@cfk3 

You receive payment on your invoice with QB Payment, correct? They are still struggling to fix this issue

https:// quickbooks.intuit.com/learn-support/en-us/other-questions/intuit-ips-found-in-spamcop-blocking-list-preventing-vendors/00/1066289

Consider having a 3rd party solution to send invoices and integrate it with your QBO and QB Payments account for the time being.