Simplify3D User Forum

I've been printing with Simplify for a few days now, and all of a sudden I'm getting this error message:

Attempting connection at \\.\COM3...
Permissions error connecting to port
Is there another application already connected to this port?
Error opening selected port.

Printer is a prusa i3. I recently changed the hot end buti don't see how that could have effected anything.

Any ideas?

Your printer can only connect to one program at a time. That messages means that something else is already connected to the printer, so S3D won't be able to connect.

Check for other apps that might be running. May also want to try restarting the computer in case it's a background process.