Servers are safer to use if a setting called "authorized fetch" (also known as "secure mode") is switched on. Ordinary members cannot activate it, it can only be activated by the server's admin.
When it's activated it makes blocks much more effective and greatly reduces unwanted interactions.
You might want to ask your server admin to switch it on. If they're unsure about it, they can find lots more info and step-by-step instructions at https://fedi.tips/authorized-fetch
