A few things I would check:
1.) Can you ping the HipChat server from your machine (hipchat.com for HipChat Cloud or your FQDN for HC Server)?
2.) If on HipChat Server, verify that you have the correct ports opened per HipChat Server System Requirements: https://confluence.atlassian.com/hc/system-requirements-for-hipchat-server-606306343.html.
3.) Are you using a proxy in front of HipChat? Can you verify 443 https in/outbound to the site from your machine?
4.) If you're still having an issue, please reach out to HipChat support at support.atlassian.com and elaborate as much as possible what you are seeing.
HipChat Server Support Engineer | Atlassian
...from the beginning. We have built up a lot of content in HipChat, with it being a core tool in our distributed company model. While it is true that we didn’t need to move to Slack immediately, we felt it...
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