VA01 AFS availability check beacame SLOW.

We are running AFS 6.7. From couple of days availability check in va01 became slow.

After Material code selection cursor is waiting few seconds after that material description and all other thing

get appear. I checked if I manually clicked on Availability check button ...it also taking time.

But days before it was working within a fraction of a second no waiting cursor.

Can any one suggest me how to resolve this problem ?