echo | openssl s_client -connect smtp.office365.com:587 -starttls smtp 2>/dev/null | openssl x509 -noout -dates
notBefore=May 22 07:01:10 2020 GMT
notAfter=Aug 20 07:01:10 2020 GMT



openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -days 10000 -nodes