I installed dynmap on my new 1.16.5 Spigot Server, but the map does not work right.
The map is an earth map that i downloaded online,
Nether does work fine, i didnt test the end.
screenshot: https://prnt.sc/1e9rudb
https://prnt.sc/1e9rudb

My suggestion:

Stop your server

In /plugins/dynmap, delete the "web" folder. *This would delete any existing map data that you have.

Once deleted, relaunch your server.

Once server is running, run a fresh "/dynmap fullrender"

Wait for render to complete, check map.

The EarthMC map has many known issues with Dynmap such as, incomplete render, only rendering where players have visited, or not rendering leaves and other foliage.
This is a result of how the map was made and is not an issue with Dynmap, luckily there is a fix.

1. Download the WorldBorder plugin: WorldBorder
2. Pause Dynmap: /dynmap pause all
3. Run worldborder with the force flag: /wb [worldname] fill [freq] [pad] [force]

• [worldname] is the name of your world folder
• [freq] is how many chunks a second are generated, 20 is the default. WARNING: setting this too high will cause server lag
• [pad] how many chunks beyond the border to generate, this makes sure that if a player visits the border, all chunks are already generated. The default is 208, I recommend setting this to 0 for EarthMC
• [force] This must be set to true

4. Wait for worldborder to finish
5. Unpause Dynmap /dynmap pause none, you may have to restart the fullrender using /dynmap fullrender [worldname]

Closing due to age, please follow steps listed above if issue still persists