Hi @lakshmi – It wasn’t clear where you are working.
If you are working at usegalaxy.org, then the server is undergoing scheduled maintenance right now. This appears to be @julsies 's situation. Working at other public Galaxy servers is an option as @hrhotz mentioned: usegalaxy.eu and usegalaxy.org.au are good choices.
If you are working at your own Galaxy server, or some private Galaxy server, it sounds like the tool did not get added to the “whitelist” that permits HTML content to be viewed or accessed. Should this be your case, whoever administrates the server can check under Admin > Manage Whitelist and mark the tools that should have output in formats that can be security concerns be accessible. (HTML cannot be Uploaded at public servers, for this very reason, but tools are configured to permit the creation/access of HTML). For a private server, the administrators can set those permissions as wanted. If done through the GUI, a server restart isn’t needed. And in most cases I can think of, end users won’t need to rerun prior jobs that created HTML – changing the setting is enough. But try a rerun/server-restart as troubleshooting strategies as needed.
Note: In the upcoming release of Galaxy 20.09, the function will be renamed. The prior setting “whitelist” will be renamed as “allowlist”. Full details here: https://docs.galaxyproject.org/en/latest/search.html?q=allowlist&check_keywords=yes&area=default
Thanks!