- Plesk Onyx for Linux
Let’s encrypt certificate installation fails when the domain has been recently created.
Apache restart interval is configured as 10-15 minutes in Plesk > Tools & Settings > Apache Web Server > Apache restart interval.
The Let’s encrypt certificate can be installed after Apache is restarted.
This is Plesk bug with ID #EXTLETSENC-504 that is planned to be fixed in future Plesk updates.
As a workaround:
Apply option Keep websites secured with free SSL Certificate for the domain's service plan in Service Plans > example_plan > Additional Services > Let's Encrypt