Hey there, it looks like you've clicked on the thread link Weasel posted, which took you to that thread on Weasel's server's website rather than opening the thread within your own server.
If you open Weasel's thread on your own server you will be able to interact with it without any problems.
To do this, copy the link to the thread (https://mastodon.social/@weaselx86/110654214305215039) and then paste it into the search box on Mastodon. This will make the thread appear on your own server 👍