The error message outputs a HTML page as json. Here's a script that changes it back to HTML if it's useful.

python
import json

html = ""
with open("error.json") as f:
    data = json.load(f)
    print(data['ctx'])
    print(data['msg'])
    for i in data['error']:
        html += str(data['error'][i])

with open("error.html", "w+") as f:
    print("See: error.html")
    f.write(html)