data directory must be owned by the webserver user in docker usually www-data. If you can’t change permission you need to troubleshoot it on the Linux level - nothing to do with Nextcloud itself.
Hi i have mounted it in fstab like this: //192.168.1.220/nextcloudstorage /mnt/nextcloudstorage cifs uid=33,gid=33,dir_mode=0770,file_mode=0770,username=nextcloud,password=xxxxx,iocharset=utf8 0 0