Unable to get local issuer certificate / Certificate period has expired

Nothing changed with the certs in the past days/weeks. There was a change in Sept 2021 as one of two intermediate certs expired. You are using the "long chain" so have this expired cert (as does this forum's website). And, this can confuse older openssl versions depending on their CA Root store. If this really is a recent change this is unlikely to be the cause. But, further reading below might help anyway