disabled network

Good Afternoon, I hope this is the right place to post this question... if not, if an admin can move it and let me know where it went, I would be most grateful.

I just got a macbook pro, my daughter, who has a macbook, talked me into
it. We use them in our start-up. We have a secure wireless router and
have no problem logging on when we get here in the morning. We do have
some problems sending mail, but that's a whole different
story(frustrating ) . The question I have is that at least 10 times a
day we get a error message saying something to the effect. "Your network
appears to be compromised, your connection has been disabled for one
minute."

We have noticed it happens when either of us logs on again, but it also
happens when we are just sitting here working. It drives us BOTH nuts. Is
there a way to turn off the safeguard since are network is already
secure????

Someone suggested it may be that my router has over-aggressive settings, however, my PC doesn't get disconnected.

Thank you for your time.. I am an OLD PC dog trying to find peace in
the MAC world.