I find your site and API very helpful for the competitive programming community. However, I found the following issue, that causes failure to my bot while fetching contests.
SSL certificate for clist.by was expired on Tue, 07 Nov 2017 08:46:00 UTC according to SSLLabs. This causes warnings when opened with browsers and failure in API calls. Please kindly renew the certificate so that your users (including bots) can continue to make use of your site properly.
I haven't tried this, but consider using automatic renewal script for every 60 days or so. Reference: automatic renewal