Breaks admin in WP

Activated the plugin and as soon as I did it other user in other computer tried to access and get an error trying to log in wp-admin due to one of the files of the plugin (sorry, didn’t get the screenshot).
I deactivated the plugin, entered with the other used and then activate again. It was not the plugin I needed so I tried to deactivate it and delete it but I couldn’t even deactivate.
It’s interfering somehow the admin panel of WP. I’ve manually deleted it.