Dark Souls III Covenant Summons

I can't seem to get summons in this game.

I have put the sigil thing on. I am standing in an area with the logo next to my health pulsating. Yet I don't seem to be summoned.

I'm trying to rank up because I just need a few of the items in the covenants and then I'll have the Platinum Trophy but nothing seems to be happening.

Am I doing it wrong? Do I need to be in a specific location for each covenant to summon me? I don't get it.

@dexda: Best place is outside a boss door. Litteraly no one needs a summon to run through a level. Also put the sun sigil on or leave it blank. No one wants a blue, purple or red in co-op.