Been playing the game for around 2 days now & its just dawned on me im not recieving any achievements as i checked the forza hub an the achievements bar is on zero also im about half way through the cup & done several achievements on the list but nothings working on any achievement on this game? Anyone else got the same problem?
Are you playing offline
You dont get achievements while offline
Definately not 
i wish it was as easy as fix as that all online even been online on the game?
you playing on PC or xbone
i had a similar problem where my pihole was blocking everything about the achievement servers. (pi hole = internal dns running on a raspberry pi and blocks all kinds of add related sites). you can have the same problem if a firewall is running on your network and it’s blocked. This was on my xbox one. if it’s on pc you do need to do a google search there might be some problems related to some services not running if your not blocking stuff from xbox live / achievements server.
these domains may not be blocked to make achievements work:
xbox.ipv6.microsoft.com device.auth.xboxlive.com www.msftncsi.com title.mgt.xboxlive.com xsts.auth.xboxlive.com title.auth.xboxlive.com ctldl.windowsupdate.com attestation.xboxlive.com xboxexperiencesprod.experimentation.xboxlive.com xflight.xboxlive.com cert.mgt.xboxlive.com xkms.xbolive.com def-vef.xboxlive.com notify.xboxlive.com help.ui.xboxlive.com licensing.xboxlive.com eds.xboxlive.com www.xboxlive.com v10.vortex-win.data.microsoft.com settings-win.data.microsoft.com
gotten from here Commonly Whitelisted Domains - FAQs - Pi-hole Userspace
Doubt its my firewall as i recieve achievements on any other game i play plus ses the same on the xbox as the app has to be a issue with this game! I mean how i havent even got the achievement for completing the first race which you have to do!
Xbox one when i open achievements on xbox one app ses played for 22hours but no achivements or driver level both on zero
So ive now messaged microsoft support & they suggested uninstalling the game an my account an re installing & the problem is still there anyone admin wise even interested in this issue or aware of it?
You wont get any official response over the weekend