Been getting this "Invalid SSL certificate" (Error 526) for a week? (more or less). Accessing through Android app and web browser from Spain.
Correct, but you don't know what is invalid.
It could be that the SSL certificate is expired (most likely) BUT it could be a number of other issues.
It could be signed by an untrusted source, it could be a man in the middle attack. It could be there's malware on the website. It could be that the SSL certificate is misconfigured.
There's no way to know because cloudflare is hiding the actual issue.