testserver is not reachable due to an 500 Internal Server Error

I would have posted this on the test server but I get the message that the site is forbidden

https://i.imgur.com/MaDJRNM.png

further trying gets an error message

https://i.imgur.com/VnwWBdW.png

An explanation of the 500 error is that is an 500 Internal Server Error

https://i.imgflip.com/8eavsk.jpg

The test server is undergoing some "work" :)