File not found

Hi folks,I am new phpmaker 2020. I got this message when I try to upload.File not found <filename.pdf> SyntaxError: Unexpected token < in JSON at position 0I’ve set up the database as follow:Attachment_Name varchar(100)
File_Type varchar(100)
Attachment longblob
File_Size int(12)In phpmaker 2020, general settings for upload is all set and max file size is 20mb. Under the table field, view tag hyperlink is set too.
In php post_max_size is set to 256m upload_max_filesize is to 256m as well.
Any file I tried to upload will get that message. (all less than the max size). Also there is no error in f12 under network.
Encrypt file path is disabled.
Any help would be great, many thanks.

File upload is done by API, normally the HTTP response is in JSON format.If the error says:
SyntaxError: Unexpected token < in JSON at position 0That means the HTTP response starts with “<”, which is probably error message in HTML (not JSON data starting with “{”), which cannot be parsed as JSON and hence syntax error.So there must be error message in F12 → Network, you need to find the request to the API (action=jupload), and click it to view the HTTP response. See https://discourse.hkvstore.com/t/uploading-image-error/1904/1 for more information how to check the HTTP response correctly.

Thank you for your help, I’ll double-check.