**************  SOLVED ***********************

I dont normally post my findings on message boards, but I thought I might help everyone who is battling with this issue.

I found the problem and the solution, the send forms dialog box uses SMTP AUTH a method for authenticating that is insecure and not enabled in Office 365, most applications use MODERN AUTH and thats where the whole problem lies. 

SMTP AUTH is basic authentication and all I had to do was enable (SMTP AUTH) on Office 365.

Sounds easy, well I will attach the links to reslove it.

Step 1 

Install Powershell 7 on your Windows PC (Find the .msi file)

Step 2 

Install the Exchange module for Powershell 7

https://docs.microsoft.com/en-us/powershell/exchange/connect-to-exchange-online-powershell?view=exch...

Step 3 

Using Powershell - Enable SMTP AUTH on your Office 365 Org or individual mailbox.

https://docs.microsoft.com/en-za/exchange/clients-and-mobile-in-exchange-online/authenticated-client...

I am posting this in the hopes that the quickbooks staff will document a formal step by step documentation for you guys. It took me a good hour to read through all the links above.. Good luck guys.