Installing addon using command line

Hi, my Hassio can’t install add-on in the add-on store with following error message. Can i install the add on using the command line? I did not manage to setup the SSH server yet due to same problem and i’m thinking to connect my Rasp Pi to a monitor, keyboard and mouse, then execute the command line and pull and install the add on from GitHub.

May i know is this doable? I don’t really want to reflash my SD card until my Hassio really broken.

Here is the error when i’m trying to install the MQTT broker,

20-01-23 01:29:00 ERROR (SyncWorker_8) [hassio.docker.interface] Can't install homeassistant/armv7-addon-mosquitto:5.1 -> 500 Server Error: Internal Server Error ("error parsing HTTP 408 response body: invalid character '<' looking for beginning of value: "<html><body><h1>408 Request Time-out</h1>\nYour browser didn't send a complete request in time.\n</body></html>\n\n"").