This is a "should I be worried" question. I access a website on my laptop via my home network/router. My Edge browser gives me a "Your connection isn't private" warning page and a NET::ERR_CERT_AUTHORITY_INVALID error. When I check the certificate it looks ok, at least within validity period, hasn't been revoked and seems to have been issued by a valid issuer.
I change my network to my mobile phone as a personal hotspot, when I now access the site it is fine. When I checked the certificate it is issued by a different authority.
My question is, can this happen under legitimate circumstances? This feels like a man in the middle attack. How would I go about troubleshooting this?