SMTP codes
One page per failure code the knowledge base's own tables document: SMTP replies, enhanced status codes and provider codes, with the articles that cover each. 211 codes, read from the articles' own tables.
24 codes below are not linked: a correction to the knowledge base row behind each one is open, and those pages are not advertised while it is.
- 4.2.2
- 4.3.X
- 4.4.3
- 4.4.7
- 4.4.X
- 4.7.28
- 4.7.X
- 4.X.X
- 4xx
- 5.1.1
- 5.1.2
- 5.1.3
- 5.1.6
- 5.2.1
- 5.2.2
- 5.3.4
- 5.5.2
- 5.7.1
- 5.7.10
- 5.7.26
- 5.7.30
- 5.7.32
- 5.7.703
- 5.7.X
- 5.X.X
- 5xx
- 421
- 421 4.3.0
- 421 4.4.5
- 421 4.7.0
- 421 4.7.0 TSS04
- 421 4.7.0 TSS05
- 421 4.7.26
- 421 4.7.27
- 421 4.7.28
- 421 4.7.29
- 421 4.7.30
- 421 4.7.32
- 421 4.7.40
- 421 IPTS04
- 421 IPTS05
- 421 RP-001
- 421 RP-002
- 421 RP-003
- 421 TSS04
- 450
- 450 4.2.1
- 451
- 451 4.3.0
- 451 4.4.2
- 451 4.5.0
- 451 4.7.23
- 451 4.7.24
- 451 4.7.26
- 451 4.7.550
- 452
- 452 4.2.2
- 452 4.5.3
- 454
- 454 4.7.0
- 455
- 500-504
- 501
- 501 5.5.2
- 501 5.5.4
- 501 5.7.11
- 502 5.5.1
- 503 5.5.1
- 503 5.7.0
- 504 5.7.40
- 512
- 523 5.7.10
- 530
- 530 5.7.0
- 534 5.7.14
- 534 5.7.90
- 535 5.7.80
- 550
- 550 5.1.1
- 550 5.2.1
- 550 5.4.5
- 550 5.5.3
- 550 5.7.0
- 550 5.7.1
- 550 5.7.24
- 550 5.7.25
- 550 5.7.26
- 550 5.7.27
- 550 5.7.28
- 550 5.7.29
- 550 5.7.30
- 550 5.7.40
- 550 5.7.511
- 550 5.7.515
- 550 5.7.606-649
- 550 5.7.703
- 550 DY-001
- 550 DY-002
- 550 OU-001
- 550 OU-002
- 550 SC-001
- 550 SC-002
- 550 SC-003
- 550 SC-004
- 551
- 552
- 552 5.2.2
- 552 5.3.4
- 552 5.7.0
- 553
- 553 5.1.2
- 553 5.1.3
- 553 5.1.7
- 553 5.7.1
- 554
- 554 5.4.6
- 554 5.6.0
- 554 5.7.0
- 555
- 555 5.5.2
- X.0.X
- X.1.0
- X.1.1
- X.1.2
- X.1.3
- X.1.4
- X.1.5
- X.1.6
- X.1.7
- X.1.8
- X.1.X
- X.2.0
- X.2.1
- X.2.2
- X.2.3
- X.2.4
- X.2.X
- X.3.0
- X.3.1
- X.3.2
- X.3.3
- X.3.4
- X.3.5
- X.3.X
- X.4.0
- X.4.1
- X.4.2
- X.4.3
- X.4.4
- X.4.5
- X.4.6
- X.4.7
- X.4.X
- X.5.0
- X.5.1
- X.5.2
- X.5.3
- X.5.4
- X.5.5
- X.5.X
- X.6.0
- X.6.1
- X.6.2
- X.6.3
- X.6.4
- X.6.5
- X.6.7
- X.6.8
- X.6.9
- X.6.10
- X.6.X
- X.7.0
- X.7.1
- X.7.2
- X.7.3
- X.7.4
- X.7.5
- X.7.6
- X.7.7
- X.7.X
- BL000000
- BL000001
- BL000010
- BL000011
- BL000100
- BL000101
- BL000110
- BL000111
- BL001000
- BL001001
- BL001010
- BL001011
- BL001100
- BL001101
- BL001110
- BL001111
- BS02
- DM000001
- DY-001
- ES000001
- ES000010
- OU-001
- PH*
- RL0000
- RL000001
- RL000002
- RL000003
- RL000010
- TS*
- TS02
- TS03