Diagnosis
The unit is struggling to meet the set point, which is usually a sign it's undersized for the room, or there's a performance issue like poor ventilation or a dirty filter.
How to Fix It
First, do the maintenance checks. Clean the air filter (a dirty filter cuts airflow massively). Ensure the exhaust hose is connected securely and is as short and straight as possible—every bend and foot of length reduces efficiency. Make sure the window seal kit is installed snugly with no gaps letting hot air in.
If That Didn't Work
Be realistic about the cooling capacity. The SPS5-10C is roughly a 10,000 BTU unit. It's designed for a single medium-sized room. If you're trying to cool a large, open-concept space, a sunny room with lots of windows, or a room with other heat sources (like an oven), it will run non-stop and never catch up.
Heads Up
Portable ACs are less efficient than window units because they exhaust hot air indoors via the hose. Some of your cooled air is always being sucked out to vent that heat, creating a negative pressure that pulls in warm air from elsewhere. It's an inherent design flaw.