I am having trouble searching for some users in Messages. Here's what I did.

Using the Chrome or Firefox web browsers (I did not try it with others) on Windows:

1. I log into https://moodle.org in the usual way.
2. I click on the messages icon in the header.
3. I try to search for either "bas" or "brands" (because I want to send him a message).
4. After a long wait, I get a pop-up message that simply says "undefined".
5. If I click the X (or anywhere else on the screen), the message disappears.
6. If try to refresh the page, I get a message that says "This site is not available currently.". This happens even if I open a new tab.

I know the site is not down, as I can open moodle.org in a different web browser, I can access Moodle.org. Also, if I clear my browser's cookies, I regain access to Moodle.org.

The attached 30 second video clip (animated GIF) demonstrates the issue. However the actual wait before the error message appears is actually much longer. See attachments.