RSS URL error

Hello,

I am having an RSS problem I can’t figure out. If I type my feed URL (https://myblog.com/feed) into my browser, I can read my feed. The feed also checks out at the W3C feed validator. However, a subscriber tells me that there’s a problem with the feed, and according to ismyblogworking.com, my feed URL is https://myblog.com/https:/myblog.com/feed/. Unsurprisingly, that doesn’t work. In the head section of my blog, the address is shown correctly: <link rel=alternate" type="application/rss+xml" title="My Blog Feed" href="https://myblog.com/feed/" />

Any ideas what’s going on?

Thanks!