ValidationError error is caused by incorrect username, password, display name or password. Could you please make sure that the inputted fields follow these rules:
username:
Min length 3, max length 48
Allow alphanumeric, underscores and dashes
Spaces is not allowed
Start and end with alphanumeric
password:
password must contain between 8 to 32 characters
Contain at least 3 of following 4 types of characters: uppercase letters, lowercase letters, numbers, special characters
No more than 2 equal characters in a row
display name:
Min length 8, max length 32
only contain uppercase and lowercase letters, spaces, special characters
start and end with alphanumeric
email address:
Min length 3, max length 256
only contain alphanumeric, at, dot, underscores, dashes, plus, ampersand, and wildcard