Installed Exchange 2016 CU18. Afterwords OWA/ECP were not working. I know this is a common issue and i've gone through all the following steps to resolve but I still have portions of ECP not working.
The OWA logon page loads fine and works correctly now. The ECP page logon screen loads fine HOWEVER once credentials are put in the page takes 10-20 seconds to load then looks like this:
It looks like that in every browser (Edge, IE11, Firefox, Chrome) and none of the links work.
I have already done the following:
Checked to make sure the correct SSL certificate is bound to the ECP web port - It had switched back to the default but I corrected this.
Removed and Recreated the virtual directories for OWA as well as ECP.
Removed and recreated the web applications for OWA as well as ECP.
Looked in all the web.config files and changed all the directory references with %ExchangeInstallDir% to static paths (there were a few)
Fixed the application settings for the BinSearchFiles in ECP in IIS. It was using %ExchangeInstallDir% as well I changed all those to static paths.
Somebody suggested just installing CU19 but I don't want to make the problem worse. I need it back up and working properly before I install anything else!