How to work around emails getting blocked by ISP?

Thanks to for the workaround for emails using mailcatcher:

More than likely your isp is blocking your email attempts or you’re being spf filtered. I set up a mailcatcher docker container (

  • Set up the mailcatcher: docker run -d --name mail -p 1080:1080
  • Start the mattermost docker container linking mailcatcher: docker run -d --name mattermost -p 8065:80 --link mail:mail mattermost/platform:helium
  • Change the config_docker.json EmailSettings to “mail:25” instead of “localhost:25” and restart the docker container (or you can modify the Dockerfile and rebuild)
  • Use the sign up now option (you’ll have to alias www.yourserver to the ip of your server)
  • Check yourserver:1080 once the email has been sent and you should see it in there
  • You’ll need to alias teamname.yourserver to get to your team page login once you’re done setting up

Basically you just need to intercept the mail going out in some manner. I just happened to have a mailcatcher from another project.