This means something (likely another instance of Geyser) is running on the port you have specified in the config. Please make sure you close all applications running on this port. If you don't recall opening anything, usually restarting your computer fixes this.
If you are using a server hosting provider and get this error, you likely need to use a specific port allocated to you. See the setup guide for instructions on how to configure Geyser.
candid trout
hollow bramble