I was surprised to find out that Cloudflare blocks me from accessing https://mstdn.ca and emailed its admin. Their answer is quoted below:

I looked at the Ray ID you provided and it appears you were blocked due to using a Russian IP address. Due to the current conflict with Ukraine, we took a stance that we would not welcome Russian traffic. While we understand that some residents may not agree with their leader, the decision stands. Additionally, Russian foreign interference into Canadian politics is rife and in an abundance of caution will not unblock Russian IPs for this reason as well. There is nothing wrong with the WAF setup, it is working as configured.