DIAGNOSIS Leaks at the hose port are almost always because the standard garden hose adapter isn't seated correctly or the rubber gasket inside is missing/misaligned. The connection is more finicky than it should be.
FIX Unscrew the hose. Check inside the plastic hose adapter that came with the unit—there should be a small black rubber O-ring or flat gasket. Make sure it's present and seated in its groove. Hand-tighten the hose connector onto the unit's threaded port clockwise until it's snug. Don't over-tighten with tools, as you can crack the plastic port. Run the hose straight down without tension pulling on the connection.
IF THAT DIDN'T WORK If it still drips, the gasket might be defective. You can try wrapping the unit's threads with a few layers of plumber's Teflon tape before re-attaching the adapter to create a better seal.
HEADS UP The pump has to push water uphill, so any leak at the connection will cause it to drain back and potentially trigger the full-bucket error. A dry, water-tight connection is critical for pump mode.