Hi:

First, it maybe goes without saying that you'll want to upgrade your server to take advantage of numerous fixes, including but not limited to security updates mentioned in these release notes and this recent forum post. In your case this would be a multistep upgrade, as covered here.

We aren't able to do detailed troubleshooting on older versions, but some ideas:

Are you seeing any error messages in the log when it hangs like that?
Any errors in the developer tools/browser console?
Does it happen on a different browser? (Chrome vs. Firefox)?
Does a timechart showing by participant groups > Show individual lines work?
Does > Show mean > None work? i.e. is it only the specific combination of showing groups with means as Std Err bars or something broader?

I am able to create a scenario to get a 'Loading...' hang like that on a timechart, but only in a study that has neither participant groups nor cohorts - this seems unlikely to be why you are seeing that, but it's worth confirming the groups you want to use are still assigned and populated.

As a confirmation of basics on that older version, you can install our example study from the 21.7 documentation archives into a testing folder. That study includes a pre-built timechart that you should be able to use 'chart layout' to show the 'std err' bars. Assuming that works, hopefully you can work backwards to what may be different in your study?

Hope that helps, and thanks for reaching out.

--Molly