Ubuntu 16.04 LTS is in "Extended Security Maintenance" mode currently, as it's rather old. This might mean you don't have a correct OpenSSL version installed. You might have OpenSSL 1.0.2 installed which has trouble with the "long chain" which is used for Android support, which includes an intermediate chained up to an expired root certificate.
It also might be your Ubuntu version is too old to have the ISRT Root X1 root certificate in its root cert store.
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