Having tried most things, I shall give my FT-710AESS one more try on FT8.
So far, everything I have tried has failed. If it is something I am doing wrong, I have yet to find out what it is! All the drivers are installed, port selection is correct, port properties are correct, rig selection is correct, RTS is selected (as they say), but still CAT fails to work.
If this fails, the rig will have to go back. I really hope I can crack it. It should not be this hard. If the rig is working, I fail to see why this popular mode is so difficult.
If you have one of these rigs, please tell me your FT8 settings both on the transceiver and WSJT-X. I thought mine were all correct, but obviously not.