I was able to get this working. I had to perform multiple steps:
- Start Exchange Management Shell as an administrator and run the following scripts: .\UpdateCas.ps1 and .\UpdateConfigFiles.ps1.
- Exit Exchange Management Shell and open a Command Prompt window as an administrator.
- Run iisreset.
Taken from here: https://learn.microsoft.com/en-us/exchange/troubleshoot/client-connectivity/owa-stops-working-after-update
After the update completed and the server rebooted, I couldn't access OWA or EAC. I then needed to create a new certificate: