There's a red broken heart icon under the server ip and it says i have to view the server logs. I honestly don't know much about servers so i have no idea how to fix it myself. I have 10 mods installed and the server version is 1.16.5.
Here is the log: https://pastebin.com/951Uxyt
Mods: abnormalscore, AdLods (Large Ore Deposits), yung's BetterCaves, creativecore, forgeendertech, mgui, tetra, upgrade aquatic, yungsapi
The mods are on versions 1.16.4 but i also have these mods installed in my minecraft and they work just fine on 1.16.5.