Gmail — No access to important emails

My Gmail account is [protected]@gmail.com.
I have subscribed to www.sara-freder com for a long time. From last few weeks I couldn't not access to the emails sent from that site. Just few days back I saw an email message from that site in my phone notifications but when I opened my email inbox, there was no such message. Again the worst thing I discovered today that all previous email message from that site couldn't be opened and even in web search I couldn't open the weblinks of this site. Instead an error message appeared on my phone screen "this site is not reachable. " Please solve this problem so that I can use my email account without any disturbance.