Amazon SNS subscription stuck on pending verification

Your software
My Mautic version is: 4.0.1
My PHP version is: 7.4.3
My Database type and version is: Mariadb 10.3
Running in EC2 instance with Ubuntu 20.4

Your problem
My problem is:

Hi, I am running the Mautic 4.0.1 running in Ubuntu 20.4 on EC2 Instance. I want to filter all the bounced emails using Amazon SES and SNS. I can create the Topic and Subscription but subscription stuck on pending verification. So my understanding is that Amazon need to call webhook in Mautic. Is there a way to check if webhook is running or working?

These errors are showing in the log:
No error logs on Mautic

Steps I have tried to fix the problem:
Followed this article Bounce management | Mautic, but still subscription stuck on pending verification.

I have the same issue, did you figure this out?

Hi, this happens if you enter

  1. wrong HTTP / HTTPS for the protocol
  2. wrong URL. For Mautic it’s different URL if you use API and different if you use SMTP.
    Which one are you using?

I am getting this error/ problem as well. Is there an article or something on this one?