In rare cases Jira Cloud displays different error messages while you're trying to access Exply. Here are the most common ones and how to fix them.
This error message can appear when you're trying to install Exply for the first time and your Jira instance provides us an yet unknown clientkey.
Unfortunately, there is nothing you can do to solve this as this is related to our infrastructure. What you can do is to contact us, so that we can solve this together.
This is the most unuseful error one can get cause it can mean nearly everything. If this error message shows up you probably also just see a light grey background instead of the Exply interface.
As we know of now there can be a weird behaviour with Safari and Firefox due to Cross Origin protections. Therefore, try to access Exply with Google Chrome. If this works, it might be something browser related.
To solve the issue that Exply isn't displayed in Safari, you can disable the Prevent cross-site tracking setting in the Safari preferences under Privacy.