Cannot select user in external Storage

[j-ed]

Instead of creating new request for the same problem, it might always be a good idea to use the search function of the forum first in the future I think this problem has already been addressed here:

External storage, available for selection

Thank you for reply. It is easy when you see it in front. Explain is sometimes difficult. [nextcloud] At the picture you can see the field I meant. At setting I choose external storages (Administration). I fill in Folder name, External Storage, Authentication, Configuration. The last field is Available for. This field is always blank. I can not choose a user of group. I tried to fill in a user myself, the NC20 recognized the user, but make the field blank again. THX, Peropjot