How can I fix the invoice delivery issue that affects all my invoices?It has nothing to do with settings or addresses being incorrect.

I am having the same issue and have had for a few months now. I seem to be able to send from an incognito tab (thought not always) and from my ipad. However, last month I did this and they STILL were not sent and none of my customers have paid me as they did not get the invoice - they all pay exactly on time so it's clear they are lacking the invoice. Quickbooks has just raised the cost for their service whilst reducing the ability to get paid - which does not make sense. It also doesn't make sense that you're supposed to clear cache/use incognito to send an invoice. Just stupid. It's worked for years - please fix this immediately. It's a fundamental requirement for a small business accounting solution - the ability to bill. I have been sending invoices to these customers with same email addresses for years - that is not the issue.