"API Gateway" -> "Custom domain names" don't work until I recreate it

I think it would be a little difficult to troubleshoot this issue on this forum. Based on the information you’ve provided, it sounds like you’ve taken appropriate first steps to troubleshoot the issue, including recreating the custom domain to restore functionality. While this can serve as a temporary solution, it’s crucial to delve deeper into the root cause to prevent recurrence and ensure consistent performance.

Given the complexity of the setup and the services and the potential for various factors to influence connectivity, I recommend to raise a support request with the API gateway team so that the team can help troubleshoot this with you. The support team will be able to best assist you by looking at the configurations of your setup and troubleshoot why this issue is seen. Please be assured that, the support team can offer insights, guidance, and recommendations to help resolve the issue effectively and ensure the stability and reliability of your infrastructure moving forward.

Please open a support case with AWS using the following link: https://console.aws.amazon.com/support/home#/case/create