This issue just started for me June 16th. I now have Invoices stuck as "Delivery Issue" that won't send out. This is going to valid working email addresses to multiple clients, it is definitely not isolated.

I'm very annoyed with the unprofessional attitude to the support specialist that told me on chat support that I need to tell my clients to get different email accounts, and when I responded that that was unacceptable they left the chat!