On deleting AWS Rest API from UI or through AWS console or terminal with command:
aws apigateway delete-rest-api --rest-api-id 1234123412
(mentioned in aws docs) I faced the error saying to delete base-path mappings related to RestApi in your domain, I tried deleting it with the following cmd given in aws docs:
aws apigateway delete-base-path-mapping --domain-name 'api.domain.tld' --base-path 'dev'
I got error: An error occurred (NotFoundException) when calling DeleteBasePathMapping operation. Invalid base path mapping identifier specified
Delete the corresponding domain name from the UI (under 'Custom domain names').
After which, the RestApi can be deleted.