I can't get the email agent to work

I'm trying to setup an email agent, but i keep running into problems and i can't get it to work.

I'm using Proofpoint as an email provider, with starttls and port 587. I have verified that the credentials work.

These are my environment variables:

• SMTP_HOST=smtp-eu.ser.proofpoint.com
• SMTP_DOMAIN=smtp-eu.ser.proofpoint.com
• SMTP_SERVER=smtp-eu.ser.proofpoint.com
• SMTP_PORT=587
• SMTP_USERNAME=123456
• SMTP_USER_NAME=123456
• SMTP_PASSWORD=123456
• SMTP_AUTHENTICATION=login
• SMTP_ENABLE_STARTTLS_AUTO=true

Username and password are redacted ofcourse, but the password uses lowercase/uppercase letters, numbers and special characters (such as > { , ) ^ = :). I'm worried it might trip over that.

I'm getting the following error: "Error sending mail to email with event 136: end of file reached"