As I said, I don't know what the problem is that AutoSSL is reporting, so tech support will have to deal with it. Make sure your Wordpress installation is up to date, as LP is starting to forcibly update older versions (which could potentially break something). You should have gotten an email warning you of this, if it applies to you. Check for updates, anyway.
You can continue to operate your site under http: (non-SSL) if you wish, but your search engine rankings will not be as good as they could be if the site was under https: (SSL). That is, there is a SE penalty for not being under SSL.
You didn't used to have a private SSL certificate (extra cost), or make use of a free shared SSL certificate, did you? If you did, maybe something is left over that is interfering with AutoSSL. Something to consider.