Recently, I found a problem that the App Store of Nextcloud always return a error message: "No apps found for your version." I found 2 reason of this issue.
Sometimes some reason, you need use the VPN to access the nextcloud.com. You just add proxy in the ~/config/config.php But if it is not working, your connection will be down.
Try to remove it or update the proxy address.
Because of the cache of redis, sometimes it cannot work well.
- Restart the redis-server
- Restart php-fpm
Try to flash that page again, I believe it will work well after that.