Even with "unblocked" versions, problems occur. Here is your fix-it list:
Eaglercraft exists in a legal gray area. It uses decompiled source code from older versions of Minecraft. Mojang and Microsoft frequently issue DMCA takedown notices to sites hosting the game. To stay safe while playing: eaglercraft 1.17 unblocked
Mojang / Microsoft have not approved Eaglercraft. Using it may violate Minecraft’s EULA (End User License Agreement), especially if it uses actual Minecraft assets (sounds, textures, names) without permission. Even with "unblocked" versions, problems occur