I recently installed the UniFi Controller 5 on my Synology NAS (DS918+). Unfortunately, after installing the package from http://synology.acmenet.ru/ the website wasn’t working. In Chrome, I would receive the following error: ERR_SSL_VERSION_OR_CIPHER_MISMATCH

Thankfully, a little bit of googling resulted in a solution here: https://community.ubnt.com/t5/UniFi-Wireless/ERR-SSL-VERSION-OR-CIPHER-MISMATCH-after-upgrading-to-5-2-7/td-p/1681242

What do you need to do to fix this:

  • SSH into your Synology and goto /volume1/@appstore/UniFi Controller 5
  • There is a system.properties file located in the directory /data
  • You can only edit this file via root access (DSM 5) or sudo (DSM 6),
    sudo vi data/system.properties
  • Uncomment the line starting with
  • Restart the package via the Synology Packager Center

Voila, that should have done the trick.