This error happens when Snowflake cannot access your S3 bucket. The most common cause is adding a prefix (folder path) in the IAM policy or creating a folder inside the bucket. Snowflake does not use prefixes, and adding one blocks Snowflake from writing staging files.

This usually occurs during the “Creating an IAM Policy” step in Snowflake’s S3 integration documentation, where it’s easy to mistakenly include a prefix.

How to fix it

Use an empty S3 bucket and remove any prefix from your IAM policy. The policy should allow access to the entire bucket.

Note: The adjustments occur in two different statements of the policy.

Object access statement:

Bucket listing statement:

Avoid using any path like <bucket>/<prefix>/* or "<prefix>/*".

Removing the prefix ensures Snowflake can create and manage its staging files, which resolves the 403 error.

A 404 error appears when the Authorization URL you entered is incorrect. This usually means the Snowflake Account/Server URL was copied incorrectly or the required format was not followed.

Correcting the Authorization URL will resolve the issue.

How to fix it

Example of the correct format:

Incorrect format (missing the required account locator pattern):

Once the Authorization URL matches the correct Snowflake format, the 404 error will no longer occur.