To complete the list of status codes, here are the SMTP Status Codes. These will eventually be replied by your mail server.
| Code |
Description |
| 200 |
(nonstandard success response, see rfc876) |
| 211 |
System status, or system help reply |
| 214 |
Help message |
| 220 |
Service ready |
| 221 |
Service closing transmission channel |
| 250 |
Requested mail action okay, completed |
| 251 |
User not local; will forward to |
| 354 |
Start mail input; end with . |
| 421 |
Service not available, closing transmission channel |
| 450 |
Requested mail action not taken: mailbox unavailable |
| 451 |
Requested action aborted: local error in processing |
| 452 |
Requested action not taken: insufficient system storage |
| 500 |
Syntax error, command unrecognized |
| 501 |
Syntax error in parameters or arguments |
| 502 |
Command not implemented |
| 503 |
Bad sequence of commands |
| 504 |
Command parameter not implemented |
| 521 |
does not accept mail (see rfc1846) |
| 530 |
Access denied (???a Sendmailism) |
| 550 |
Requested action not taken: mailbox unavailable |
| 551 |
User not local; please try |
| 552 |
Requested mail action aborted: exceeded storage allocation |
| 553 |
Requested action not taken: mailbox name not allowed |
| 554 |
Transaction failed |
