Thank you 'xrobwx71' for responding.
It ended up being an issue with the Microsoft 365 service account that I use. They have something called 'Windows Information Protection (WIP)'. Unless specifically specified, when in private mode you are restricted to what local devices you can access unless you explicitly add it to your trusted/allowed list.
Information about it can be found here:
Windows Information Protection (WIP) app protection policy - Microsoft Intune
Once I removed my computer from Azure AD, I was able to access the websites of local devices on my network. (I did this through Settings – Accounts – Access work or school and removed the account which was listed.
I will add it back once I’ve learnt more about WIP. I’m surprised this issue hasn’t affected more people using Microsoft 365. At the very least, the policy should be set to allow access to local devices otherwise you’re locked out and need alternative means to access your resources.
Hope this helps someone and I really appreciate you taking the time to respond to me.
Kind regards
Boyd
