External storage after new Installation


I use Nextcloud for many years now and mostly for my personal use, e.g. calendar, contacts, tasks and notes and so on. I host it on an UBERSPACE.de in Germany.

Now I had to switch the UBERSPACE server, because the old one would no longer be maintained.

I did a backup of my database and a fresh install of Nextcloud version 18.0.3 on the new server where I used the database from before. Everything works fine except my external storage. Its mounted via sftp to my HTCP at home.

I get this message when I try to change the settings for the external storage via the frontend:

Interner Serverfehler

Der Server konnte die Anfrage nicht fertig stellen.

Sollte dies erneut auftreten, sende bitte die nachfolgenden technischen Einzelheiten an Deinen Server-Administrator.

Weitere Details können im Server-Protokoll gefunden werden.

Technische Details

  • Entfernte Adresse: xx.xx.xx.xx
  • Anfragekennung: ********************

I can’t correct the settings, because the frontend does only show this error message. So I went looking for the settings and because its only one user and one storage in the database I found these tables and deleted every record in it:

**oc_external_config **

Still I get the same error. So I deleted everything concerning external storage in

But the error stays. In the nextcloud log I get this entry:

{“reqId”:"*********************,“level”:3,“time”:“2020-03-31T10:39:50+00:00”,“remoteAddr”:“xx.xx.xx.xx”,“user”:“hans”,“app”:“PHP”,“method”:“GET”,“url”:"/index.php/core/preview?fileId=23&c=36a0df37e6866308b9ef3e46f56535d7&x=750&y=750&forceIcon=0",“message”:“stat(): stat failed for /home/hans/nextcloud_data/appdata_xxx/preview/23/500-500-max.png at /var/www/virtual/hans/nextcloud.hans.de/lib/private/Files/Storage/Local.php#144”,“userAgent”:“Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:74.0) Gecko/20100101 Firefox/74.0”,“version”:“”}

I can’t find another entry in the database. I did a new installation multiple times but can’t get rid of this error. I hope anybody can help me. Where the heck does Nextcloud store these external storage informations?

Many thanks in advance.