Q: smart cover doesnot wake up ipad air anymore

Hi yeast2u,

If your iPad Air's sleep/wake feature no longer responding when connected to your smart cover, try disconnecting the smart cover and checking the magnetic connectors for any foreign material. You can use the tips in this link for cleaning your iPad and cover. 

Cleaning your Apple products

If you find that there are no debris on the connectors, try a simple restart and if necessary, a forced restart for the device. Restart your iPhone, iPad, or iPod touch 

These steps should have your smart cover working as it did before. Thank you for using Apple Support Communities for help. 

Have a great day