You’re running a version from 2013. That is very very very obsolete, unsupported, and no longer suitable for use on the internet due to the plethora of security vulnerabilities.
You might be able to upgrade to a supported version (19.07 or 21.02), but I doubt that will be possible based on the age of your device and/or the fact that it may be built on an SDK that is not the official openwrt project (based on OpenWrt, but not the real deal).
Ultimately, it is almost certainly time for a new device.