HTTP load failed (error code: -999 [1:89])

With the upgrade of Xcode to Version 10.0 (10A255). The error "HTTP load failed (error code: -999 [1:89])" shows up on the Xcode debugger when trying to make a post request with images onto a server. It was working fine before the Xcode and iOS 12 upgrade, nothing has changed on code or the backend. The error description furthermore reads "The operation couldn't be completed. (NSURLErrorDomain error -1012)".
Please also note, I have the TLS set up on my plist.
Is it a bug on Apple's side or are there new permissions or changes needed in code.

Regards.