Hello @ShowFromShuhov,
welcome to the community 
You started a topic in support category. Unfortunately you ignored the template and a lot of information to help you is missing. Please edit your original post and add all required details like Nextcloud version, webserver type and version, os version, related log file content. Use the support template.
Without additional information the community members cannot help you.
your issue seems like a DNS or network issue, see
check your router setup or contact support at https://support.keenetic.com