Directory names on Nextcloud not accessible


I have following problem. Using the standard file explorer, I can not access direclty all folders on my Nextcloud, some of the folder are not visibles. However, in the Nextcloud Webspace they are available. I can access to the files, when writing myself the folder name.

Also, some folder names are indicated in the Web environment with a kind of translation to French. For instance, the coorect folder name “STAGE FORMATION” is translated to “FORMATION DE SCENE”, or “MON COURS PREMIERE” becomes “LUN COURS PREMIERE”, I guess, MON ist interpreted as “MONDAY” and translated to “LUN”(di) which is monday in French. I have somehow the feeling, that both topics are related?
Below Screenshot is illustrating both issues:

  • “STAGE FORMATIO” becomes “FORMATION DE SCENE” on the Web environnement
  • “Première réforme” is not available in the Explorer
    Any help is appreciated.