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Certificate/key pairs cannot be imported in the server any more, and the certificate check output looks like this:
An OpenSSL function used to check for certificate validity erroneously requires IPv6 to be enabled on the loopback interface. Check whether IPv6 is enabled by running the ip addr ls command; if IPv6 is enabled, the output will look like this:
On the other hand, if IPv6 is disabled, the output of ip addr ls will look like this:
In this case, certificate validation will always fail, and you will need to apply the workaround.
Re-enable IPv6 on the server and reboot it.