Starting back on the 4th for me the gateway webpages stopped loading properly in Firefox and Chrome. Of all things, they seem to load great in Edge. The most offending pages are Config-Licensing, Status-OPC Connections, Status-Logs, and Status-Execution. No project is necessary, just install fresh then click around.
Tested on Windows Server 2012R2 and Windows 10 just now. Build b2019030702
Just click wildly on different links in the gateway website and some will not load any content aside from the license count down timer up top and side bar. Sometimes if you keep clicking they will load. See screenshot below.