Everything was fine, everything it worked. Until all of a sudden the Greater Band of Aura stopped working on armor, Band of Mana, etc. I tried anything possible, like changing the Greater Band of Aura to a new one, replacing it in the slot, changing slots, restarting the complete client and so on. I even crafted a regular Band of Aura to double check, but nothing works. And its not like it is a configuration error or something like that, because it used to work until a couple of days in the past.
Please help, thank you.

I checked the Band of Mana too and it works in the Mana Pool. And like I said, even if it would not work, my armor and pickaxe should get mana from the Greater Band of Aura, but it didn't in roughly 20 hrs of active game.

Now I found out, that every time I equip my Tainted Blood Pendant with Speed II in it, Mana Regen stops working immediatly as well as it starts working immediatly after I unequip it.

I really can't do much with just "it stopped working".

What else do you want to know?

I need info on your environment, mods loaded (a log is prefered as it has more info) and a screenshot of your inventory.

http://pastebin.com/BgR3RnxK
http://pastebin.com/A0YZgMxz

ROG Maximus VII Ranger
Intel i7-4790K
Windows 7 Ultimate x64
Intel HD Graphics 4600 (no external graphics card)

Corsair Vengeance 8GB RAM

It doesn't work because you don't have anywhere to store the mana.

The description says, that the mana goes in "mana containing items" which obviously should include items like the armor. That said I had a Greater Band of Mana and it did not work with that either until it glitched away, so I do not have it anymore.

The armor doesn't contain mana, it uses it.

I will try it again with a new Greater Band of Mana soon. If it won't work I will tell.

I tried it now with a Mana Tablet and it works indeed. Seems like it was a temporary or server related glitch.
Anyway, thank you very much for your help and investment of your time in the issue i mentioned.

Well I noticed there is still an issue left. Mana Regeneration stops when equipping a Tainted Blood Pendant.

Of course it does, the pendant consumes mana as well, so you get a negative delta.