Problems
The errors that only happen with fishing.
Install, framework and database errors are under Problems in Setup.
No prompt at the water
The spot is off, or the player is outside its range. For a custom spot, the coordinates are still the ones from the example.
The menu opens without a rod
Rods are inventory items and the player owns none. Check that the item names in your inventory match the keys in Config.Rods.
The catch never arrives
addInventoryItem in the adapter is answering false, or the inventory is full. A catch that cannot be handed over counts as a miss on purpose, so nothing is lost silently.
Item pictures are missing
Config.ItemImage points at a path that does not exist, or at the right folder with the wrong extension. The shipped set is SVG.
The market pays nothing for something
The item has no price in Config.Items. That is the switch for what is worth selling.
Experience is gone after a reconnect
Config.Database.enabled is off. Experience is then held in memory per connected player and is dropped when they disconnect. Catches are only ever written to the database, so without one they are not kept anywhere. What lives in memory is the running session, and it ends when the player stops fishing, disconnects or the resource stops.