Have looked through the FAQs but can't seem to find the answer to this.

I am trying to play 5 DL, 3 LB, 2 CB and a FS.
I keep being told that it is an illegal formation. I have Left End, Left Tackle, Nose Tackle, Right Tackle, Right End, OLB Left, OLB Right, MLB, CB Left, CB Right, Safety Free Middle.

But even if I move the Nose Tackle to play Strong Safety, a basic 4-3 formation, apparently it's still an illegal formation. Why would this be? Is it because I've got 5 DL players on the field?

But even if I play one of them as Strong Safety?

Where is the list of formations that are allowed?

I'm having same problem on Offense, yet I'm using the same formation that I did last game.
2TE, 2RB, 1WR, 5OL, 1QB.

....TE..LT..LG..C..RG..RT..TE........WR
.....................QB......................
................FB...........................
.....................HB......................

I used this formation last week, now it seems to be illegal?

on defense?