Cannot equip offhand weapon

Dual spec shaman, I use Outfitter 4.2.6 - when I switch to enhancement spec, I cannot equip the offhand weapon, it fails with the error "This item cannot be equipped".
I tried to equip it manually with the same error.
I can equip both weapons in the main hand with no issues.
I am sure this is not an Outfitter issue. The 2 weapons I have are 2 one-handers, not specific for main/off hand.
Everything else equips correctly with no problems.

I had no issues last time when i switched specs (a few days ago).

I tried to go back and forth between the 2 specs several times, with the same result.

Please advise.

Did you retake duel spec in your talents? js

I don't use Outfitter but I too had same problem.. the fix was unlearn talents and redo .. worked after that

Re-speccing fixed it. Thank you.
However, if I have to re-spec every time this issue comes up, that is not a fix.

Appreciate the help.