I'll recommend update osTicket to the latest version. You can download the latest version from here.
For Microsoft Office365 emails, you'll probably need to install and configure OAuth2. You can download the plugin at the link above. Follow the OAuth2 guide for Microsoft here.
If you prefer to have osTicket fetch mail to create tickets, you'll need to enable fetching (Busqueda de Email), in the main settings page in your screenshot and configure the Remote Mailbox tabs of the system emails. Also create a cron job to run the fetching routine, following the guide here.
