The web acl is associated with the Application Load Balancer in the AWS region. After a few hours, it is found that the association has been cancelled

I want the web acl to be associated with the Application Load Balancer in the AWS region, after a few hours, I found that the association was cancelled, repeated many times with the same result, and in the Application Load Balancer configuration item integrated service (AWS WAF) shows: This Application Load Balancer does not support WAF, I don't know where the configuration is wrong，thank you