Run these lines on your command line one-by-one to ensure they are properly set. Make sure you replace the yourdomain.com, dkimKey and verifyCode variables before running.
now dns add yourdomain.com '@' TXT zoho-verification=verifyCode
now dns add yourdomain.com '@' MX mx.zoho.com 10
now dns add yourdomain.com '@' MX mx2.zoho.com 20
now dns add yourdomain.com '@' MX mx3.zoho.com 50
# SPF