Website opens only on some devices

Nameservers across the world refresh with different schedules, depending on the ISP. Thus, you just need to wait until your website becomes operational.

Whilst your website is not accessible with one provider, it can already be accessible with another.

You can check website accessibility from different locations worldwide using the service http://www.locabrowser.com/.

So, all you need to do is wait, and your website will become accessible after your ISP refreshes their nameservers.