I guess it shouldn't affect Authentication though..Billing Maintenance: 2 NOV 7:00AM PDT
We will be taking down the commerce system for maintenance at 7 am PDT (14:00 London Time) on November 2nd for 3 hours. The following systems will be affected by this maintenance:
Buying gems from the gemstore
Purchasing from the official website – https://buy.guildwars2.com
Thank you for your understanding.