mistic.mizoram.gov.in is currently affected by Let's Encrypt-based rate limits (https://letsencrypt.org/docs/rate-limits/). You may review certificates that have already been issued by visiting https://crt.sh/?q=%mizoram.gov.in . Please note that it is not possible to ask for a rate limit to be manually cleared.
The 'Certificates per Registered Domain' limit (50 certificates per week that share the same Registered Domain: mizoram.gov.in) has been exceeded. There is no way to work around this rate limit. The next non-renewal certificate for this Registered Domain should be issuable after 2020-12-08 17:38:37 +0000 UTC (38h46m0s from now).