The error message 'We were unable to load Disqus. If you are a moderator please see our troubleshooting guide.' may occur while using the popular Disqus Comment System. If you encounter such a message, please try to resolve it using the following methods.
Add your site to the "Trusted Domains" list
This error might occur if you have not added your website to the "Trusted Domains" list in Disqus.
Please check whether or not your site has been added to the Trusted domains list by going to Disqus Admin > Setup > Advanced. If not, please add your domain name to the Trusted domains list.
Remove double quotes in the post titles
If the problem continues even if you have added your site to the Trusted Domains list, please try to remove double quotes in the post tiles. You might be able to change double quotes ("...") to single quotes ('...') or remove them.
The above figure shows a post tile containing double quotes in its title. I think this workaround will work in non-English sites. (I suspect that the curly qutoes might caused the problem.)
Disqus Comment System - SEO friendly
I installed the Disqus plugin in my WordPress blog. But a user reported that the Disqus Comment system does not in my blog. I found that Disqus didn't work with the error message "Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user's experience. For more help, check https://xhr.spec.whatwg.org/." I disabled the Disqus plugin and then embedded Disqus by using the Disqus API. This resolved the issue.
You can easily integrate Disqus into your WordPress blog. Please refer to the following:
It's easy to embed Disqus into WordPress. Disqus is also SEO friendly and will attract more traffic into your site.