I've done research for the last couple days concerning tethering Fedora 28 x64 bit over an android tethering.
The android phone is a non-standard AOSP with functional APN settings. I recently switched from OpenXT hypervisor to a standard Fedora build, and began to experience select issues with tethering over the android platform. The issue was reproduced using a Windows 10 KVM guest, though I'm not how the network stack would change, if at all for underlying delivery of the packet.
Wireshark captures (attached, and available as a pcap) show that the client is unable to reach out specifically, and receive an acknowledgment from the server, resulting in "Cannot contact reCAPTCHA. Check your connection and try again".
Similar specific, isolated occurrences were observed elsewhere as well--routing overall through the android phone is successful.
Pardon missteps in structure, or correcct Exchange. Any help is appreciated.