The issue: Whenever a user tries to send invoice they sometimes experience 1 of 3 issues. 1) Quickbooks freezes and they are forced to end the program ad start over. 2) Outlook crashes and they have to close out of quickbooks and relaunch both programs. 3) the whole computer freezes and they have to restart their PC. This is very intermittent, sometimes never happens, sometimes over 10 times a day. This issue is affecting our entire site (3 users). All three users have different PC's but same-ish specs. 

Specs: All users have Dell machines, one is a Latitude E5550, the other two are Dell Optiplex 3060s.

All computers are using QB Desktop 19, Windows 10 1903, Office 365, Adobe Acrobat DC pro.

Trouble shooting steps: I have made sure that outlook is the default email app. Made sure all firmware and software is up to date. I have installed Quick books Tool Hub and ran every tool that thing had to offer. When i called Quickbooks about the issue we ran though a lot of troubleshooting steps for almost 3 hours. There are clear errors in the event viewer(EV) when the issue appears however the QB tech told me that they dont use EV as a source of issues. Finally when we couldn't get the issue resolved I was told to use a different supported mail app.

This is not exactly a satisfactory answer as the whole business uses Outlook as its standard email application, and QB supports outlook as a usable app.  

Has anyone has this issue and if so how did you resolve it?