I got this situation and I have no idea why it caused SMTP code 503...please help me.
This is what I tried to do. I try to run my program and send warning email if a condition is satisfied. But I cannot receive any warning emails so I use a lan analyzer to detect what's wrong...and I got this SMTP code 503. What will cause this problem and how can I solve this problem. My program runs fine with other Linux 9.0....not sure which setting in Linux I should modify...Any idea????