This has got to be related to the fact that Sage (for some odd reason) is still running it's software at 32bit when the rest of the world has moved on to 64bit. 

We are having issues sending emails now. We have the 32bit version of Outlook 2013 but have been advised not to install 32bit of 365. If we install the 64bit then it won't work with Sage.

Honestly, Sage should be prioritising moving over to 64bit.

This has got to be related to the fact that Sage (for some odd reason) is still running it's software at 32bit when the rest of the world has moved on to 64bit. 

We are having issues sending emails now. We have the 32bit version of Outlook 2013 but have been advised not to install 32bit of 365. If we install the 64bit then it won't work with Sage.

Honestly, Sage should be prioritising moving over to 64bit.

It's nothing to do with 32bit Vs 64bit in this case. From my initial research it looks to be related to a 3rd party component we are using to interact with Outlook. this was introduced to avoid the poor user experience created through the heavy-handed security changes that that Microsoft added to Outlook several years ago. I'm still investigating an exact root cause but can confirm it's not a 'bitness issue'.