Owncloud on Synology not working anymore .ocdata and data path problem

Server
1

Owncloud is running on a productive System on a Synology (DS 416). Owncloud was running like a charme for a long time. Suddenly, I got the message (translated from german in english, therefore I might be slightly different)

  1. Message
    "The file-folder (/volume1/owncloud/) is invalid. Please ensure the data path has a file called ".ocdata"."

  2. Message
    "The creation of the "data" folder is not possible (/volume1/owncloud/). This can be repaired, by the webserver ."

The 2nd Message ends with an empty space and without the solution. Furthermore I checked everything. The .ocdata is available, the data folder exists... I have absolutely no plan what to do. The only thing I also did on the same day was, that I updated phpmyadmin that required mariadb 10. Therefore I have now mariadb 5 and 10 running. But I don't think that this causes the problem (owncloud is running on mariadb 5).

I would be thankful for any help!

2

There are perhaps permission problems? Can you show us the output of:
ls -lisa /volume1/owncloud

and df -h