Hi Alex, you're getting that error cos your domain name does not have an SSL certificate and anyone who tries to access your app using "https://" will get the error message.
I tried your link and it was the same thing... but when i removed the 's' and just used 'http' it went through.
content on your app as follows-
"Now your pet has the opportunity to loosen up by your side
and take pleasure in the comforts of your apartment home in Allen.
Large dogs, multiple pets, restricted or aggressive breeds…
We’ll help you find the best Pet friendly apartment that is perfect for you!
Contact us NOW! (682) 990-3845
so just remove the 's' and use only 'http'. but you should try and get an SSL certificate for your domain name otherwise anyone having https enabled in their browser won't be able to get through. ANd right now facebook is doing a campaign asking everyone to switch their profiles to https mode.
hope this helps