SMTP address & password
Once you are logged into your MailGun account, go to Sending > Domain settings > SMTP Credentials TAB.Select the desired domain and create a Sender
After creating the Sender, a pop-up notification with the password will appear. Copy it
Use the copied password and email address to connect to the warm-up
Private key (important and recommended)
It is very important to specify the private key when connecting so that the warm-up system can work correctly and without interruptions
Go to the MailGun cabinet, to the profile section