Hi,
Below you have the command that downloads the repository key for Zentyal 7.1 Development:
wget -q https://keys.zentyal.org/zentyal-7.1-packages-org.asc -P /etc/apt/trusted.gpg.d/zentyal-7.1-packages-org.asc
The repository ‘/etc/apt/sources.list.d/zentyal.list’ should be configured as follows:
deb [signed-by=/etc/apt/trusted.gpg.d/zentyal-7.1-packages-org.asc] https://packages.zentyal.org/zentyal 7.1 main extra
If the issue persists, you should check the server's time, it might be wrong, and because of that, the certificate error.
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