UNIVERSAL CLIPBOARD IS BUGGY AS HELL!
There are a lot of users with this problem, check here:
https://www.reddit.com/r/MacOS/comments/51afxn/universal_clipboard_not_working/
I have tested everything written in that post on Reddit and the thing just refuses to work as advertised.
Back to my Mac: Check (stupid as hell that this has to be turned on? It is a just a security problem to deal with if you don't need it).
Bluetooth and WiFi: Check
iPhone showing under WiFi connections: Check
Handoff: Check
iPhone and Mac paired via bluetooth: Check
...
Seems like a buggy as hell function Apple rushed out from beta into the wild.
For me the stupid thing just work one way: From the iPhone to the Mac. And there is a stupid small delay every time you are going to paste something on the Mac anyway.
From the Mac to the iPhone it has just worked one or two times. When you tap on paste you just get this super annoying delay of almost 10 seconds and the action fails miserably. When you try again the iPhone just pastes the previous local clipboard content available but not the content from copied from the Mac.
Is is a pity seeing how lately Apple just rushes things out with terrible quality control into the users. The "just works" slogan is just a joke painted in our faces these days.
I am on an iPhone 7 Plus and a Retina MBP 2015 both with the latest OS updates.