The add-on once worked fine, but now every attempted connection to nitter.net results in this: "Did Not Connect: Potential Security Issue. Firefox detected an issue and did not continue to nitter.net. The web site is either misconfigured or your computer clock is set to the wrong time. It’s likely the web site’s certificate is expired, which prevents Firefox from connecting securely."

The solution (apart from fixing nitter.net) would be to offer several OTHER pathways to Nitter. TRhere are plenty of others.