why i can not send a message

I'm having a similar problem with the Xbox App for my iPhone. I was able to use the messaging just fine a few days ago, but now it says I can't because of a security setting. I've checked my account and nothing has changed, the only security setting for
messages is still set to allowed. Following the Support link for Reputation Check just takes me to my basic security information that has nothing about messaging. And of course, I can't get any desktop browsers to load my messages either, so it just seems
all around broken.

So is it saying that when you press your home button and try to go to your messages you get an exclamation point within a triangle? If that's the case most the time it has been an Xbox services issue.

Another thing could possibly be is that if there is another account on your Xbox that got communication banned then it sometimes will block your communications too. It is an issue no one can fix because no one can notify the XBLEPT because there is no way
to contact them.

Could you walk us through what happens when you try to send a message?

do you get any error codes or error messages pop up when you go to send a message?

Are you able to load/view messages you have recieved?

No, you don't need gold membership, Just hold the power button for 10 sec

No, you shouldn't need gold for messaging, have you had an enforcement ban? If not power cycle your Xbox, by holding down the power button for 10 seconds.