Sounds like you need a consult. There a multiple reasons why a page may be slow to load. First you have to check it is even pulling the json from the F5. Quite often web pages call multiple things and only some of it comes from the F5 which people don't realise. The next thing is network congestion, or even slow browser execution, a common one is DNS but the real check is the server your requesting it from. Is the server responding in a reasonable timeframe. If you pull the json using curl from the command line on the F5 you will get an idea of the response time. There are so many factors is one of the reasons I recommend a consult. At least this gives you a start. Also it may be worthwhile popping info F5 community chat t.me/f5announce