Issue uploading C# function to AWS Lambda - not authorized to perform: iam:PassRole"

This likely means that the account you are using to connect to AWS (LambdaDeveloper, it looks like) does not have permission to create Lambda functions. Go into the IAM section of the AWS console and see what permissions and policies are associated with the LambdaDeveloper user, and make sure that the proper policies have been attached.

For example:

• Go to IAM > Users
• Click on the LambdaDeveloper user
• Click the blue "Add permissions" button
• Choose "Attach existing policies directly"
• Search for "AWSLambda_FullAccess" and click the checkbox next to it
• Click the blue "Next: Review" button
• Click the blue "Add permissions" button

Then try to upload your Lambda function as before.

Note that this is the down and dirty approach to verify that it's a permission problem. Instead of attaching permissions directly to a user as above, it would be better to create a User group (e.g. "developer"), attach the Lambda permissions to that group, and then associate the user with the group. Also, you may not want to grant "Full Access" to Lambda, but something more constrained to the purpose at hand. That can be quite a long topic, so best left for another time.