I was trying to update a plugin on Wordpress, Thrive Leads to be specific and I got an error on Wordpress, I contacted Thrive Leads technical support and they told me that the problem comes from CloudFlare, here is a screen capture of the error.
You could try pausing Cloudflare and seeing if you still have an issue.
You can pause Cloudflare from the Overview tab of the Cloudflare Dashboard, bottom right under Advanced Actions.
If the issue persists after Cloudflare has been paused, it means that there is an issue with your origin, Cloudflare is only operating as your DNS provider while it is paused.