Hey gamoxristos,
How have you been doing new installations of Cayenne? …Jessie should be re-installed on the SD card (as a new image) and then the new Cayenne installation can be installed. My fear is you installed a new installation of Cayenne onto an SD card that had a previous version of Cayenne installed on it. (side note: we are coming up with a way to uninstall Cayenne completing from the sd card so you will not have to write new images every time)
You shouldn’t have to create an account again, you can generate a new Cayenne install by adding another Pi to your account. (View image below)
We are working on a way to allow this configuration. It was also reported here How do I save the GPIO setup? - #3 by bestes
Thanks for working with us on this!
-B