Question: How can I resolve 400 error messages when modifying my Aurora DB instance?

I want to modify an Amazon Aurora DB instance, but when I make a modification request, I receive a "Status Code: 400" error message.

Short descriptionWhen you initiate an API request, AWS performs initial syntax checks to make sure that the request is complete and has the mandatory parameters. There are multiple reasons that you might receive a 400 error on an API request to modify your Amazon Aurora DB instance:Your request is denied because of API request throttling.Your parameter combination isn't valid.Your value for the input parameter is missing or not valid.The API is missing either a required parameter or an action.Browser issues caused the API to fail.You have an outdated version of the AWS Command Line Interface (AWS CLI).An internal event affected the service and caused the API to fail.Follow the relevant troubleshooting steps to resolve each of these issues.

ResolutionNote: If you receive errors when running AWS CLI commands, make sure that you’re using the most recent version of the AWS CLI.Throttling ExceptionAPI request throttling caused your denied request. These API call limits are at the account level, and they're not specific to any service.Note: You can't increase or modify limits for a particular call. AWS makes sure that API calls don't exceed the maximum allowed API request rate. This is true whether the API calls come from an application, a call to a command line interface, or the AWS Management Console.To avoid this error, take the following actions:Use exponential backoff and jitter.Instead of initiating all the API calls at the same time, distribute API calls evenly over time.Not valid parameter combinationIf you use a combination of parameters when you modify your DB instance, then you receive a 400 error. To resolve this issue, use only valid parameters and arguments in the API call.Missing or not valid parameterAWS denies your request if you use a value for the input parameter that's missing or not valid. Before you modify your DB instance, check that you included all mandatory parameters and fields in the API request.Browser issueIntermittent browser issues might cause your API call to fail. To resolve browser issues, clear your cache, and then issue the API again. If this doesn't work, then try again in a different browser.Outdated CLI versionIf you use the AWS CLI to issue the API request, then make sure you're using the most recent version. Earlier versions of the AWS CLI might not support certain parameters. It's a best practice to regularly check that your version is up to date. For more information, see Confirm that you're running a recent version of the AWS CLI.Internal eventsAn ongoing issue or internal event that affects Amazon Relational Database Service (Amazon RDS) or one of its dependent services might cause a 400 error. To check if there's any ongoing issue, review the AWS Health Dashboard. Continue to monitor the dashboards for an update on the root cause and resolution.

Related informationHow can I fix an Amazon RDS DB instance that is stuck in the incompatible-parameters status?Common errors (Amazon RDS API reference)