I'm having this problem too. I wonder, does anyone know if there's a way to discover other apps/programs that might also use the same shortcuts as copy/paste that might be interfering? I need to do some more poking around to make sure it's the OS, my browser, or ... ??? ... but so far Chrome and Safari are both giving me the same issue. However, it's in the same site where I'm having the issue. I'm working on a newsletter online in Constant Contact -- so maybe it's a Constant Contact issue. However, I'm on deadline and don't have a lot of time to try to figure it out right now. OK - non-helpful venting going on right here -
TL;DR version
1. I went to System Pref/keyboard/shortcuts and didn't see any "warning" triangles
1a) Note: I closed all my programs and restarted computer too.
2. I can't paste at all: I have tried using the keyboard shortcut, the Safari (and Chrome) menus, and using the mouse. The paste function is completely grayed out. I can copy the text and paste it back into the same field, just not into a different field.
3. A reason I am wondering if it might be a constant contact issue is I tried typing the address into the field (I was trying to create a web link to an article) and I could not type in the field.
I am all over the place - sorry if this is unclear. If anyone has questions/insight/an article to share -- any help would be appreciated. Thx. jem.