The door is locked by magic, and i cant get in, i used knock spell to open it, but that didnt work either.... what do i have to do to get in :/

I had this same problem once, but unfortunetly I can't remember what I specifically did that allowed me to enter. I think I revisited The Seven Son's at night and that did the trick. However, I might have activated (or re-activacted) this quest without realizing it. Not sure? Maybe you could try going to the Flaming Fist Headquarters and talk to Scar again, maybe that will do it?

Did you tell Scar at the gates that your from Candlekeep and you stopped the Iron Shortage?? Maybe telling him that triggers the quest.

Hey i did tell scar that i was from candlekeep and i saved the mines.....

I believe you're thinking of the Merchant League Headquarters, not the Seven Suns. (Easy to get them mixed up: They're the same general type of building, look roughly the same from the outside, are quite near each other on the exact same map, and have the same type of--um--inhabitants.)

The door to the Seven Suns shouldn't be locked at all, but you CANNOT enter the Merchant League HQ--ever--unless you accept Aldeth's quest.

Ooo, maybe i am gettin them mixed up.... so where can i find this Aldeth?

Do you recall back when you traveled through the Cloakwood Forest on your way to the mines, coming across a cabin with a hunter standing outside it. He asks for your help in fighting some tree-huggers (actually Druids)? The fella standing outside that cabin is named, Aldeth Sashenstar. If you never saw him, or were never approached by him, then you cannot do the Merchant League sub-plot (unless you trek back to meet him). If you did speak with Aldeth and decided to help Seniyad the Druid, then you can't enter the Merchant League and try this sub-quest either. Think back now, do you remember meeting this guy? And if you do, what was your response to his dilemma?

If he skipped Aldeth the first time around, he may have screwed himself out of the Merchant League subquest: Due to a bug in the game, you have to speak to Aldeth on your first trip through Cloakwood 1, or Aldeth will act like you were rude to him, and wander off in a huff.