Create SSL certificates with Lets encrypt and certbot

brew install certbot
certbot certonly --manual \
    --config-dir ~/.letsencrypt/config \
    --work-dir ~/.letsencrypt/work \
    --logs-dir ~/.letsencrypt/logs \
    -d '*.try.purplepip.com'
chmod -R og-rx ~/.letsencrypt/

During the challenge process, add the specified TXT record in your DNS configuration and visit https://dnslookup.online/txt.html to check that the TXT record is deployed, or

dig -t txt _acme-challenge.try.purplepip.com 

Note that namecheap DNS management, only enter in the relative part of the challenge domain i.e. "_acme-challenge" in the host value.

To get the cert

cat ~/.letsencrypt/config/live/try.purplepip.com/fullchain.pem | pbcopy

and to get the RSA private key

openssl rsa -inform pem -in ~/.letsencrypt/config/live/try.purplepip.com/privkey.pem \
    -outform pem > ~/.letsencrypt/config/live/try.purplepip.com/rsaprivatekey.pem
cat ~/.letsencrypt/config/live/try.purplepip.com/rsaprivatekey.pem | pbcopy