If you're still getting dropped notes or an inconsistant MIDI stream from your controller, you need to check to see if your controller is sending realtime MIDI messages.
Realtime MIDI messages like MIDI Time Clock (MTC) and Active Sensing send a constant stream of messages whether you're playing or not. It's fine to use MIDIjet to send these messages. However, it causes problems if you're sending time-critical note on/off messages at the same time. When you try to do both at once, you're likely to get jitter or hung notes.
Look in your controller's user manual to see how to turn off these messages.