Not wishing to tell you how to suck eggs - make sure it is wetted thoroughly before tightening.
Palomar knot is good and easy to tie, I've been using it a lot more lately.
But do test it.
Pound shop, most supermarkets, expensive ones, cheap ones, ESP, others I can't remember all go after a short while.
The best one's I've had so far were short and stumpy and cost £1.00 of the tackle shop counter; not sure which make if any.
I take it your using the knotless knot?
If so try fewer turns.
The picture is a bit fuzzy, could just be my eyes though, the knot does look a bit messy; have you formed a 'D'?
I was just about to post that all scissors go blunt after a while, so I have found out something new
Instead I will say that most scissors go blunt after a while, especially when you use them
I think the customs office would blow a cog.
No nets
No bait
No used hooks
No used line
Following to be fumigated
Camo
Bivvies
Reels
Rods
Rod holdalls
Footwear
Clothing
I wouldn't blame them either, look what's happened here.