This week's book giveaway is in the Programmer Certification forum. We're giving away four copies of OCP Oracle Certified Professional Java SE 21 Developer Study Guide: Exam 1Z0-830 and have Jeanne Boyarsky & Scott Selikoff on-line! See this thread for details.
- Does this problem happen only in the local server, but not when deployed?
- Are you sure you are NOT including the Javamail JAR files in the classpath? (Appengine SDK has the Javamail stuff embedded, which is what you should use)
- Are you sure the sender ID (which is "email@domain.com" in your example) has administrative permissions, at least in a 'viewer' role?