regional SSL problem.

Some countries do have firewalls that block access to sites, depending on content and location. A helpful way to confirm which countries are having difficulty is to use ping.pe. You can enter your IP address to determine which countries may not be able to access your site. If users from non-firewalled countries are also having trouble, consider whether they're using a mobile device, as your site may not be configured for IPv6 (the preferred network for mobile devices).

As for why SSL is an issue but your site was fine previously, there are some suggestions in this StackExchange thread. It could have to do with your website sharing its IP with others, or it could be blocked by default until whitelisted.