Fund1

A little late, but I can confirm that "sudo usermod -a -G dialout [your_username]" did the trick for me. Actually I neater found nor did the trick, it came to me by "accident" as I installed Arduino IDE (for playing with Marlin FW), and it did it all for me.. It was never Cura, just a stupid permission, however there is a way for software to ensure the needed permissions to work, so here we are.. (BTW RepetierHost and Repsnapper now works for me as well)