Why did exchange email suddenly stop working?

[Fudgetech]

Two days ago I started getting timeout errors on my email app connecting to my company exchange server. Now it only works on wifi. Testing with my network manager revealed secure sites for our company are not reachable from Telus mobile network. On wifi everything works normally. I have rebooted a few times, tried different apps and its the same on all.

[Nighthawk]

Have you checked with your employer to ensure their firewall isn't blocking anything? I can't see Telus randomly blocking access.