I have a problem in cloud formation. Error when using Fn::Join with a parameter
问题 I am trying to create one Security Group and calling other security group from parameters using cloudformation. I used this as a resource however I get the following error message from cloudfromation Template validation error: Template error: every Fn::Join object requires two parameters, (1) a string delimiter and (2) a list of strings to be joined or a function that returns a list of strings (such as Fn::GetAZs) to be joined. AWSTemplateFormatVersion : 2010-09-09 Description: "simple web