Assembly: How to solve problems of the assembly of the pencil unit through the File Manager in Xubuntu?

I have Xubuntu 18.04 and I can not have the pen drives mounted when I click on them in the file manager. I have a Failed to mount "PEN DRIVE LABEL". Not authorized to perform the operation. emerging error

This is a new installation. I think this problem is related to my LDAP authentication that I use for years, from Ubuntu 14.02 or even earlier. I have been using all the versions (not LTS too) of Ubuntu or Xubuntu and I have never had any problems with the assembly of the pendrive. With 18.04 I can not make it work. I know that without my LDAP configuration, mountings through the File Manager work well. I also know that mounting the same pen dirs on the command line as root works fine.

I think my problem is related to a new set of policies (from perspective 18.04) that is not compatible with my LDAP session login configuration.

My question is: how can I solve the problem of the pen drive assembly process started in the File Manager in order to find out what I should change (in my LDAP login configuration or elsewhere)?