Error message when updating Lambda runtime

Thank you for the reply. I tried using both root user and IAM user to update the runtime version, but received the same error message. This is how I attempted to update runtime:

1. select the specific function in Lambda;
2. scroll down to "Runtime settings" and click on the "Edit" button;
3. select from the runtime dropdown list "Node.js 20.x";
4. click "Save". After these actions, I received the error message: The role defined by this function cannot be assumed by Lambda. May I know where I should put the above code you shared, please? Thank you!

Thank you for confirmation. I tried upgrading in the same way in my environment, but the error could not be reproduced.

May I know where I should put the above code you shared, please?

This is what is set in the trust policy of the IAM role used by Lambda. You can check the IAM role set from Lambda settings.

Once you open the IAM role, check the trust policy.

Thank you so much for providing the above guidance! Really appreciate it. I followed the above steps and realised that the corresponding role cannot be found. i.e., I clicked on "Configuration", followed by "Permissions". Under the "Execution role", it shows the "Role name" and then the "Resource summary". The "Resource summary" currently indicates that the role cannot be found. May I know what does this imply, please? Thank you!