Sectigo is currently experiencing degraded performance with its issuing platforms. Users will experience delays with free SSL certificates being issued or renewed as a result.
You can view Sectigo's status page here:
https://sectigo.status.io/
We will provide further updates as they're made available.
UPDATE: The SSL issues with Sectigo were resolved around 2:00PM Eastern Time, however delays are still happening. Please reach out to support if your SSL certificate isn't generating.