Bathroom Drain Plug Leak

[diy-ammo]

Hi.

I have recently removed the drain cover to clean it and I noticed that the previous gasket is gone.

I am now facing a leaking drain and would like to get some tips on what's the best way to fix this?
Remove the old silicone seal and reapply new bathroom silicone or I can find these for sale somewhere online, as the usual suspects of Amazon etc haven't got it.

Appreciate your help guys.

I believe it's a standard 1 1/2" 70mm drain.

 

[diy-ammo]

I have also started cleaning the residue of silicone and wanted to assess the leak and see it from the underside.

Whilst moving the drain assemble, I noticed that it was barely connected and came off with a light push. I tried reattaching it and I can't seem to find a way to reattach it securely.

Am I doing something wrong? I tried screwing it together, but it barely connects/reaches it.