Turn off notifications for that service check.
See the docs for more info, since it sounds like you might have missed most of what nagios is all about.
Reading the docs at least once is not going to hurt anyone. It doesn't take all that long and well worth the effort. But please, I won't hand feed anyone, when the docs spell out the answer to such easy and obvious questions.
Honest, I'm not triing to be mean. I'm just being honest and doing this for your own good.