Let's Encrypt SSL certificate installation failed: Failed letsencrypt execution

Hello i have installed the let’s encrypt extension for plesk and i get a error when i would like to generate a certificat for my domain .

Let's Encrypt SSL certificate installation failed: Failed letsencrypt execution: 2016-01-12 11:24:32,369:WARNING:letsencrypt.cli:Root (sudo) is required to run most of letsencrypt functionality.
An unexpected error occurred:
There were too many requests of a given type :: Error creating new cert :: Too many certificates already issued for: toevenstay.com
Please see the logfiles in /opt/psa/var/modules/letsencrypt/logs for more details. 

But it’s true that I had already generated for my field because I remade many times my server in two days, so I wanted to know how to unlock it especially since I do not have backup of this folder.
Thanks in advance and sorry for my bad english .

There is a rate limit of 5 certificates per domain per 7 days.

You will have to wait a week before you can get another certificate.

If you are testing, you need to use the staging / test server.

it’s not possible to delete old cartificate ?

If you have the old certificate, you can continue to use it ( each of the 5 you already have is valid for 90 days).

No, “deleting” or “revoking” a certificate does not change the rate limit of 5 certificates issued per domain per 7 days…

If you do not have a backup of the certificates already issued to you, than the only option is to wait.