Satellite messaging is not like cellular messaging. With cellular, it's almost instantaneous when you have service. With satellite messaging, you don't maintain a constant connection. We rely on brief connections to send small bursts of data. The whole process is generally quick, but it can take several minutes even in good sky visibility. Low-orbit satellites are constantly moving across the sky. This is why the signal LED light is constantly changing from green to yellow to red. This is NORMAL. When the LED is green, it will send or receive pretty quickly.