Document upload and knowledge errors from api

Hello,

I have three questions for you:

1.When I upload a document via API, the agent cannot respond to questions; however, when I add the same document through the Studio menu, I can get answers to questions. When I compare the documents, I can't see any difference. They both appear to be connected to the same knowledge base. How can I resolve this issue?

2.When I upload documents in PDF format via the API, I get an 'Invalid PDF structure' error, but I don't have any problems when I convert the same document to a text file (.txt).

3.When I receive an incorrect or erroneous response from an agent, how can I capture this error? Where can I view the logs?

Thank you.