Exchange has been a mess for years
About a decade ago, I decided to play with Exchange on a NAS that I have. I had a TechNet subscription which allowed me to get Server 2012 R2 and Exchange.
My first try: I install Server in a VM. I first installed the Essentials experience for the great backup it had. I then went to Microsoft's website for instructions on how to install Exchange. I followed the instructions to the letter. But Exchange didn't work. Neither by powershell nor by the new web browser interface. After getting nowhere trying to fix it, I finally discovered Essentials is incompatible with Exchange. Exchange didn't say that during the install.
Second try: So I format the VM and install Server 2012 again. This time I only installed the features and roles Microsoft said Exchange needed. Then I again followed Microsoft's instructions to the letter. Again, Exchange didn't work. Neither by powershell nor by the new web browser interface. After spending days looking up articles to fix the problem, I gave up and bought a book.
Third try: When I looked at the instructions in my book, I noticed quickly it had a step Microsoft never mentioned. I followed the book's instructions to the letter, and finally Exchange worked! I could do what I needed to do in the browser interface ...
... for a month. This was a server in a VM. I didn't touch anything in it. The backend of Exchange was still working, powershell was still working, but the browser interface didn't work anymore. The only that happened was Microsoft install security updates. I left the VM server completely alone, never changing anything. And Exchange broke itself. But since the calendar and email was still working, I left it alone. A year later, both stopped working. I changed nothing on the VM server. Not Exchange powershell worked. It completely broke itself.
I decided then and there that Exchange is not worth the trouble. It was such a broken mess that I don't know how anybody keeps using it. My experience was the pre-SatyaNad days, before he decided to get rid of quality control people to boost stock prices. I can't imagine how horrible it is now that even more testers have been shown the door.