"This Opperation Could Not be Completed"

[Chosen King VemNem]

I keep getting this pop up whenever trying to slot support skill gems, level 1, in clearly open and usable slots (the skill is able to be used, it isn't grayed out nor not supported by the weapon.)

Anyone else getting this and may have a possible solution to fix?

[Bimjee]

Try remake the area or go to another

[Praefator]

Support gems have attribute requirements, you can see them when you hover over a support gem (like +5 Str).
At the top of the Skills menu (press G key), you'll see the number of skill gems you can equip based on your current stats.
You get one slot of each kind of gem for each 5 points in the respective attribute (Str/Dex/Int).
To see your attributes go to the Character menu (press C key).
The "This Operation Could Not be Completed" message appears when you're trying to go over your gem budget.
The error message can definitely be improved.

[Diminutive]

Are you sure you have enough stats for it?

For each type you need 5 stat of that type one, so if you had 40 of a stat you can slot 8, while 7 in another you can only slot 1.