404 page on image upload attempt since installing SSL

As stated in title: ever since I’ve installed an SSL certificate on my site, image upload attempts result in a 404 error. Not sure this is a plugin issue but thought I’d ask. If it helps please feel free to test on the page where I’m having the issues: https://flyguys.net/fishing-reports/flyguys-net-ice-off-2017-fishing-reports (please just put “test” in the comment so I can later delete. Thanks for any help in advance! Cheers … KW