Same issue I am also facing , I am unable to create Agency and getting Same error but no response from Upwork technical Team, This is very Serious issue and It seems upwork team unable to fix issue. This is really bad experience with Upwork cause of poor support.
Thank you so much. BTW is there any direct contact email or phone number of Upwork where i can file my problem to get solution immediately. If you have, kindly share with me. I need to create my agency account on Upwork ASAP. Thank a lot