Client error (status 400) for /api/template/createApp

AppSheet AppSheet Q&A
1

I am getting some errors when trying to add data to a new application. Either never ending loading times or these errors:

  1. Tables must specify a column structure. For some reason, the app definition has been corrupted. It may also be possible that you left your column structure in an inconsistent state. Delete and re-add the table to create the column structure.
  2. Client error (status 400) for /api/template/createApp

Data location in AWS Dynamo N.Virginia region. Nothing corrupt with the data as have another application using the same table.

4

Hi @captainjack,

That error can be frustrating/misleading. I think your right, most likely it’s not corrupted. Usually, that 400 error just means AppSheet is either timing out or getting blocked while trying to scan your table to figure out the column structure on its first try.

Here’s a quick workaround:

  1. Create a blank Google Sheet with the exact same column headers as your Dynamo table.

  2. Add one row of fake data.

  3. Build your new app using that Google Sheet instead.

  4. Once the app successfully generates all the columns, go into Data > Tables and just change the source path over to your Dynamo table.

If you try that and the issue still persist, then here are some more things to check:

  • Double-check that the IAM role you’re using for this specific connection has dynamodb:Scan and dynamodb:DescribeTable permissions for the N. Virginia region.
  • If you happen to be using GCP Integration Connectors to connect to AWS, make sure “authentication override” is turned off in the settings, as there’s a known bug that throws this exact error.

Hope this helps!

2 Likes