All sorted now:
Thank you all for your help.
Is there a way to install a specific version of a plugin? I accidentally uninstalled DB Search plugin and when I install it again, it's installing the latest version v0.1.0 and it is not compatible with nodebb v0.5.7. I want to install DB Search plugin v0.0.16.
If you wish to install version 0.0.16 specifically, the command would
npm install email@example.com if I'm not mistaken.
That worked. Thank you.