Illegal Formation Question

[reddeviljohn]

Just a quick question I couldn't find the answer for.

I've been running the following formation and keep getting 20% ball possession:

.....ST ST ST


ML MC MC MC

.....DC DC DC
..........GK

From reading the "Illegal Formation Rules" I can't seem to find the reason I'm receiving a possession penalty... Maybe my Strikers?
All my players are in their correct positions. All help is appreciated.

bcoz u have nobody on right side, u need either a MR or RB