I have a Raspberry Pi 3 and I am struggling with installing Mosquitto.
It seems to be caused by a bad
deb https://repo.mosquitto.org/debian jessie main
It could not find any updates (it gives a 404 error all the time).
Could someone send a valid
mosquitto-jessie.list with its contents?
(I have tried to download it again with wget)
I am getting hints to install from Instructables.
It seems also that this is duplicated with this topic