Hammer of the Gods "Can't use Skill"

Firstly new to the game so don't bash me if the answer is bleedingly obvious.

Level 75 Warrior|Titan. STR is 405 at the time of this post. Yesterday I was running with the Guild and Hammer of the Gods worked just fine. Switched up some gear (Upgrades) after those group runs. Now the Hammer of the Gods Skill is grayed out and says "Skill can't be used".

I'm using a 2-H Mace (STR requirement is 126 so 126*3 = 378 (Triple STR requirement) and Giants Blood with Shield. I have a 3-link Hammer of the Gods at the moment. At the moment for Hammer of the Gods I have a 3-Link, Fist of War Support Requirement +5STR (75), Primal Armaent (Support Requirement +5 STR) & Eternal Flame (Support Requirement +5 STR). Does that mean the STR requirement on Hammer of the Gods is cumulatively 225 (75*3) and that is on TOP of the 2-H Mace STR requirement of 378? When I hover over the Skill Hammer of the Gods it's STR requirement is "133". I even pulled all of the Support Gems out of the Skill and it still says "Skill can't be used"

It'd be helpful if the tooltip advised where the attribute deficit is as obviously there's a computation to determine why it can't be used in the first place.

Any Warrior experts here that can point out what I'm clearly missing?

Thanks for listening.

*Update*

I removed Shock Totem from the Skill list and now I can use Hammer of the Gods. Clearly I had too many Skills so the STR requirement wasn't met.