Real Time Plotting Tool ( Oscilloscope )

Hi.
I got the same problem, no curve, reset cards did not help.

Tried and end Simplot, then start up the serial monitor (in Arduino software)
The serial monitor is built up a string that looks like this

üìÿíüàü¤ù¡ü¥ü¥ü ü ø¡øàøàøàôà

Which I assume means that the data it receives from the program in Arduino.
Closes the serial monitor, restart Simplot, but no curve.
Both Simplot and serial montitor acts as connected port 18

What might have gone wrong here?

Thank you in advance