So going to assume here that you may not have the password properly set (in the right file). Depending on how/what egg you used, it may be tossed into another directory. In general, when you get the "Reached maximum retry attempts" it's one of two things.
- The physical connection can't be reached.
- RCON password isn't set properly.
Now with Pterodactyl, these do depend on the hosting environment (shared environment or your own dedicated/virtual server), with a shared environment you typically can just have support fix your issues (blocked port, incorrect startup params, etc etc..). In pterodactyl you have to specifically state the external ip or otherwise use the funky (172.1X.0.X replacing X with the corresponding digit for your docker network subnet and ip used by the container).
As for the two indicators, it is pulling your external IP so we know the issue isn't related to that (which is a good thing and is the first indicator). The second indicator is the actual error itself from the stacktrace, it tells us that it was completely unable to reach the server with the corresponding IP and RCON Password.
To double check here, for my install specifically (which we go back to the "egg" word I mentioned above) we had two separate directories that we had our files in. Make sure that you are using the proper directory for the dedicated.cfg and that the setting for rcon is set to the password IW4MAdmin uses.
In IW4MAdmin itself, make sure that the config /Configuration/IW4MAdminSettings.json has within the Servers block the correct RCON Password used for the server.