Can not access my website after trying to access wp-admin page

All,

I am having this weird issue which it just hard to troubleshoot. Two days ago, my website (www.nynjphoto.com) was working fine. I tried accessing https://www.nynjphoto.com/wp-admin page using Crome and I got following error:

“No data received. Unable to load the webpage because the server sent no data”.

Again, I tried again to access https://www.nynjphoto.com and I got following error:

Network Error (tcp_error)
A communication error occurred: “Operation timed out”
The Web Server may be down, too busy, or experiencing other problems preventing it from responding to requests. You may wish to try again at a later time.

All other websites were working so I ignore the issue for a day thinking it may be temp issue. Yesterday, again my website was working but after trying to access wp-admin page, it stopped working. I was able to reproduce the issue on my Verizon and AT&T phone. So far I tried following:

1. Tried multiple computers
2. Tried multiple ISPs
3. Tried resetting Router + Modem
4. Tried ipconfig/dnsflush
4. Tried clearing browser history

My website is not working on the PC where I tried to access wp-admin page but I was able to access the site if use proxy. While I was unable to access the site on my PC, I check https://isitdown.us/ and it shows my site is up.

Any help is appreciated.