ive set up github, with vercel. I get a good JSON code and I have deleted all of the previous tools and have a custom getcalendar tool following all the documentation on the website and chatgpts advice. i am still getting the missing nango configuration error and it isn't retrieving it. Is vapi not working with nango is this a known error? Can I have someone from support look at my code for my assistant or something to show me what I am doing wrong? i have tried everything and the online documentation says i did everything right