One day, the iLO4 web interface stopped opening on the servers, while iLO5 opened successfully.
For example, when opening through the Firefox browser, an error was displayed:
SSL_ERROR_NO_CYPHER_OVERLAP
To solve the problem I tried to lower the SSL requirements in all browsers, but it did not give any result, I even thought about updating the iLO4 firmware via SSH, but I successfully opened it on the iPhone in the Safari browser.
After that it became clear that the problem was on one computer, and as it turned out, the reason was in the AVG antivirus, when I disabled it, iLO4 successfully started to open. By the way, this is not the only problem with the AVG antivirus, it also blocked receiving mail via Mozilla Thunderbird from a corporate mail server (on different computers).
See also my article:
Updating iLO 4 firmware