Problem when integrating the infobip plugin on mautic

I have a problem with the infobip plugin download at this link https://www.mautic.org/mixin/infobip-sms/. In fact when I install this plugin and after configuration it does not allow me to create a new message, or even a new campaign. I would like to note that without this mautic plugin works normally
but after installing this plugin the two problems mentioned appear. How to solve these problems?