Official procedure is "AFCS off" for ground taxi, but it works with "AFCS on" though.
Had no issues with ground taxi right now...my procedure after engine start:
both cond. levers to flight idle
all fuel pumps on, XFER off
GEN 1 & 2 on
PWER XFER left/right off
APU GEN off, APU off
AFCS off
steering to unlocked/swivel steering
release parking break
adding like 20% torque
checking actuators in GND mode (INST page)
GND switch/light active on MFDs
Nevertheless there are some people having trouble with ground taxi. I also checked with a buddy who has the same issues, he did everything right but he was not able to gain any forward motion...