After installing letsencrypt now website won't load!

after installing letsencrypt using “sudo box install letsencrypt” now website won’t load

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This site can’t be reached

37.xxx.xxx.xx refused to connect.
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This site can’t be reached

mydomin.me ’s server IP address could not be found.
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This site can’t be reached

ns3xxxxx.ip-37-xxx-xxx.eu refused to connect.
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I try to access website using all 3 ways but quickbox or anything won’t load.

can anyones please help me how to fix this?