Install Dynmap and test a bounded world render

Dynmap publishes Minecraft terrain through a web map. Initial rendering can be expensive, especially when several map styles or dimensions are enabled. Confirm a small area works before scheduling a full-world render.
Prepare the installation
Obtain a Dynmap build that explicitly supports your server software and Minecraft version from the project's official release links. Do not assume a build for an older server can render new blocks correctly. Record the current JAR, Java runtime and world identifiers before an upgrade.
Stop the server, take a completed file backup and keep an off-server copy. Preserve 
plugins/dynmap/, any separately configured tile directory and database details. A world backup alone may not contain an external tile database. Read backups and restores before replacing an existing setup.
Set an allocated map port
Follow plugin installation, then start once to generate Dynmap's files.
Confirm that Dynmap enables. Stop again and open 
plugins/dynmap/configuration.txt.
Locate the generated web-server settings. Set 
webserver-port to an additional TCP port assigned to this service by CloudExa. Do not assume the documented default is available.
Review the enabled worlds and map styles. Begin with the intended public world rather than publishing every dimension automatically.
Start and check Console for binding, configuration or storage errors. Test the map address from a separate device.
An allocated port and a listening web server are both required. A DNS record does not allocate a port, and an HTTPS browser address requires a TLS-capable arrangement. Ask support about proxying a domain rather than installing a second web server inside a managed game container without a plan.
Render a small test first
As an authorised administrator standing in the intended world, use 
/dynmap render to render a nearby tile. That is a useful first check before a larger job. Review the map in the browser and verify the world name, orientation and terrain style.
For a broader test, consult the installed release's radius-render syntax and choose a small, recorded radius. Monitor the console, tick time and free storage while it runs. Increase one variable at a time, such as the area or number of map styles, so you can see which change affects resource use.
Upstream provides 
/dynmap pause all to pause rendering and 
/dynmap pause none to resume. These affect map rendering; they are not game-server power controls. Avoid purge commands as a routine response to a blank map because they remove generated map data and may require an expensive rerender.
Investigate the correct layer
A connection timeout usually calls for checking the listener and allocated port. A working web page with an empty world calls for checking rendering, world selection and storage. Old-looking tiles can also be a browser or proxy cache issue; compare a new private-browser session before deleting anything.
Provide support with the Dynmap version, server ID, failed URL and relevant render error. Further reading: installation, commands and configuration settings.
Looking for another plugin? Browse the Minecraft plugin guide directory.