AdSense says that my website is down, but it isn't

I'm trying to make new adsense account, I made website and sent it to google. They are rejecting it 3 times for reason:

Site down or unavailable


We found that your site was down or unavailable. We suggest that you check your application to see if there was a typo in the URL you submitted. When your site is operational, you can resubmit your application. We’ll be happy to take another look at your application.

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First time when they rejected me website was slow, it was rated 55/100 on https://developers.google.com/speed/pagespeed/insights/ . I fixed it, compressed photos, installed cache plugin, etc and now it is rated 85/100. I think that it is really good rating and loading speed. Rating 85/100 is for mobile, for PC it is 98/100.

After that I applied two more times and they rejected me with same reason "Site down or unavailable". It i is pissing me off, because website is up whole time and it is fast.

What can I do?

Google has been rejecting alot recently with very little information on why. I have also received a similar denial which stated my site was unreachable or still "Under Construction". A friend of mine is getting denied with a message about making sure he doesnt manage another adsense account even though this is the first time he has ever applied for adsense.

Do you have an SSL certificate for the site you applying with?