Is it possible to add roundcube plugins or install roundcube using ssh

i added a pointer to webmail
https://mail.mycodelab.is-cool.dev/
it shows the following error
Oops... something went wrong!
An internal error has occurred. Your request cannot be processed at this time.

For administrators: Please check the application and/or server error logs for more information.

mycodelab1 We do not install plugins for Roundcube. Roundcube is a standard PHP script that you can install on your own, and it doesn't require contacting us for assistance. The subdomain mail.mycodelab.is-cool.dev does not point to anything publicly, and this is not an issue on our side.