Esphomeflasher Permission denied: '/dev/ttyUSB0' when flashing binary

Very new to this. ESPHome add-on would not recognise my CP2102 USB module and only offer OTA to flash my Sonoff switch. I installed the esphomeflasher module (OS linux Mint).

I run esphomeflasher from the command line which presents a GUI. When I insert the module, linux finds it /dev/ttyUSB0. Command lsusb also lists it.
I hold the reset button down while connecting the module to the USB port to put it in programming mode. A red LED always shows which I assume is the power indicator.

However, an attempt to flash comes up with an Permission denied: ‘/dev/ttyUSB0’
The module CP2102 is brand new. Are these temperamental?

Has anyone seen this?

What does this say?

ls -l /dev/ttyUSB0

And

id

Hi Nick, thanks.
I was on the same path. I tend just not have enough understanding of linux. Permission to use or write to /dev/ttyUSB0 is linked to groups dialout and root on my linux box.
The command ls -l /dev/ttyUSB0 shows that. Thanks!

I’ve added myself to the group dialout using:
$ sudo usermod -a -G dialout *myusername

I had to reboot (or logout) which I found strange thinking the command would have immediate effect. I have just written the compiled binary to the switch. Great. Progress.
Thanks for your help!

You need to log in again when adding yourself to a group. group membership is set at login.

Glad you got it working.