Help with path that shows for media uploads

When I upload any media file the path shows like this

//mydomain.com/filename.jpg

Unfortunately having the “//” instead of “https://” is generating an error for an xml utility I am using. I really need it show the images file paths as https://www.mydomain.com/filename.jpg and I would be all set but can’t figure out where this “//” configuration is coming from.

I tried this plugin but it had no effect:

https://www.ads-software.com/plugins/wp-original-media-path/

Any thoughts or suggestions would be much appreciated!