What's Causing This Error
This error indicates that the client could not authenticate with the email server. It can be the cause of multiple reasons, for example:
- The user did not enter valid credentials when logging in.
- The user did not verify with the multi-factor authentication mechanisms enabled.
- The user did not have the correct SMTP settings configured.
Solution - Here's How To Resolve It
The user may follow the steps mentioned below to resolve the most common issues that could cause this error:
- The user must check if the credentials in use are valid.
- The user must make sure that they complete all multi-factor authentication challenges.
- The user must make sure that the client configurations contain the following valid SMTP configurations:
- SMTP server address
- TLS Port number (if applicable)
- SSL Port number (if applicable)
Other Common SMTP Errors (and Solutions)
- SMTP Error 101
- SMTP Error 111
- SMTP Error 221
- SMTP Error 250
- SMTP Error 420
- SMTP Error 421
- SMTP Error 422
- SMTP Error 431
- SMTP Error 432
- SMTP Error 441
- SMTP Error 442
- SMTP Error 446
- SMTP Error 447
- SMTP Error 449
- SMTP Error 450
- SMTP Error 452
- SMTP Error 453
- SMTP Error 454
- SMTP Error 455
- SMTP Error 458
- SMTP Error 459
- SMTP Error 471
- SMTP Error 451
- SMTP Error 500
- SMTP Error 501
- SMTP Error 502
- SMTP Error 503
- SMTP Error 504
- SMTP Error 510
- SMTP Error 511
- SMTP Error 512
- SMTP Error 513
- SMTP Error 515
- SMTP Error 517
- SMTP Error 521
- SMTP Error 522
- SMTP Error 523
- SMTP Error 530
- SMTP Error 531
- SMTP Error 533
- SMTP Error 534
- SMTP Error 535
- SMTP Error 538
- SMTP Error 540
- SMTP Error 541
- SMTP Error 542
- SMTP Error 543
- SMTP Error 546
- SMTP Error 547
- SMTP Error 550
- SMTP Error 551
- SMTP Error 552
- SMTP Error 553
- SMTP Error 554
- SMTP Error 555
- SMTP Error 556
- SMTP error: data not accepted
- SMTP error from the remote mail server after end of data
- SMTP connect error 10060
- SMTP error: could not connect to SMTP host
- SMTP error port 465
- SMTP timeout error
- SMTP syntax error command unrecognized
- CodeIgniter SMTP Mail Not Working
- SMTP Not Working in Python
- SuddenLink SMTP Server Not Working
- SMTP Is Not Working On The Server
- SMTP Port 465 Not Working
- Moodle SMTP Error: Could Not Authenticate
- Django SMTP Sender Refused
- The SMTP server requires a secure connection 5.7.57
- SMTP Error Codes
View all errors
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