ERROR: The certificate of ‘repo.percona.com’ is not trusted.

Hi to all,
since yesterday I can’t install mysql percona via apt on Debian 8.
The error, as I try to add the repository, is this: ERROR: The certificate of ‘repo.percona.com’ is not trusted.
Apparently the certificate is invalid.

Anyone can help me?

​Thanks in advance.

Solved adding --no-check-certificate option on the wget command-line