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Big Sur smtpclient.apple connection to smtp.gmail.com reports failure on Mail Connection Doctor

The Mail Connection Doctor reports "Trying to log into SMTP account failed." Review of the log (below) suggests the "501 5.5.2 Cannot Decode response" is caused by the * (unexpected) cancel(?) issued at 12:04:23.704 which I assume leads to the failure status!


Is the "Check Again" simply trying to end the session because there is no actual email to be sent?


Curiously other (postfix) servers I connect to do not use the same command sequence and this doesn't seem to impede sending outbound emails via gmail.


Is there a configuration setting that I might be missing? Cheers, Frank.

-----------------------------------------------------------------------

INITIATING CONNECTION Jan 04 12:04:21.876 host:smtp.gmail.com -- port:587 -- socket:0x0 -- thread:0x6000052b1040


CONNECTED Jan 04 12:04:21.991 [kCFStreamSocketSecurityLevelNone] -- host:smtp.gmail.com -- port:587 -- socket:0x60000629dc20 -- thread:0x6000052b1040


READ Jan 04 12:04:22.286 [kCFStreamSocketSecurityLevelNone] -- host:smtp.gmail.com -- port:587 -- socket:0x60000629dc20 -- thread:0x6000052b1040

220 smtp.gmail.com ESMTP a15-20020a63e84f000000b0043b565cb57csm19136637pgk.73 - gsmtp


WROTE Jan 04 12:04:22.286 [kCFStreamSocketSecurityLevelNone] -- host:smtp.gmail.com -- port:587 -- socket:0x60000629dc20 -- thread:0x6000052b1040

EHLO smtpclient.apple


READ Jan 04 12:04:22.562 [kCFStreamSocketSecurityLevelNone] -- host:smtp.gmail.com -- port:587 -- socket:0x60000629dc20 -- thread:0x6000052b1040

250-smtp.gmail.com at your service, [123.208.20.153]

250-SIZE 35882577

250-8BITMIME

250-STARTTLS

250-ENHANCEDSTATUSCODES

250-PIPELINING

250-CHUNKING

250 SMTPUTF8


WROTE Jan 04 12:04:22.562 [kCFStreamSocketSecurityLevelNone] -- host:smtp.gmail.com -- port:587 -- socket:0x60000629dc20 -- thread:0x6000052b1040

STARTTLS


READ Jan 04 12:04:22.829 [kCFStreamSocketSecurityLevelNone] -- host:smtp.gmail.com -- port:587 -- socket:0x60000629dc20 -- thread:0x6000052b1040

220 2.0.0 Ready to start TLS


WROTE Jan 04 12:04:23.168 [kCFStreamSocketSecurityLevelTLSv1_2] -- host:smtp.gmail.com -- port:587 -- socket:0x60000629dc20 -- thread:0x6000052b1040

EHLO smtpclient.apple


READ Jan 04 12:04:23.435 [kCFStreamSocketSecurityLevelTLSv1_2] -- host:smtp.gmail.com -- port:587 -- socket:0x60000629dc20 -- thread:0x6000052b1040

250-smtp.gmail.com at your service, [123.208.20.153]

250-SIZE 35882577

250-8BITMIME

250-AUTH LOGIN PLAIN XOAUTH2 PLAIN-CLIENTTOKEN OAUTHBEARER XOAUTH

250-ENHANCEDSTATUSCODES

250-PIPELINING

250-CHUNKING

250 SMTPUTF8


WROTE Jan 04 12:04:23.436 [kCFStreamSocketSecurityLevelTLSv1_2] -- host:smtp.gmail.com -- port:587 -- socket:0x60000629dc20 -- thread:0x6000052b1040

AUTH LOGIN


READ Jan 04 12:04:23.704 [kCFStreamSocketSecurityLevelTLSv1_2] -- host:smtp.gmail.com -- port:587 -- socket:0x60000629dc20 -- thread:0x6000052b1040

334 VXxxxxxxxxU6


WROTE Jan 04 12:04:23.704 [kCFStreamSocketSecurityLevelTLSv1_2] -- host:smtp.gmail.com -- port:587 -- socket:0x60000629dc20 -- thread:0x6000052b1040

*


READ Jan 04 12:04:23.974 [kCFStreamSocketSecurityLevelTLSv1_2] -- host:smtp.gmail.com -- port:587 -- socket:0x60000629dc20 -- thread:0x6000052b1040

501 5.5.2 Cannot Decode response a15-20020a63e84f000000b0043b565cb57csm19136637pgk.73 - gsmtp


WROTE Jan 04 12:04:23.974 [kCFStreamSocketSecurityLevelTLSv1_2] -- host:smtp.gmail.com -- port:587 -- socket:0x60000629dc20 -- thread:0x6000052b1040

AUTH LOGIN


READ Jan 04 12:04:24.247 [kCFStreamSocketSecurityLevelTLSv1_2] -- host:smtp.gmail.com -- port:587 -- socket:0x60000629dc20 -- thread:0x6000052b1040

334 VXxxxxxxxxU6


WROTE Jan 04 12:04:24.247 [kCFStreamSocketSecurityLevelTLSv1_2] -- host:smtp.gmail.com -- port:587 -- socket:0x60000629dc20 -- thread:0x6000052b1040

*


READ Jan 04 12:04:24.519 [kCFStreamSocketSecurityLevelTLSv1_2] -- host:smtp.gmail.com -- port:587 -- socket:0x60000629dc20 -- thread:0x6000052b1040

501 5.5.2 Cannot Decode response a15-20020a63e84f000000b0043b565cb57csm19136637pgk.73 - gsmtp


WROTE Jan 04 12:04:24.519 [kCFStreamSocketSecurityLevelTLSv1_2] -- host:smtp.gmail.com -- port:587 -- socket:0x60000629dc20 -- thread:0x6000052b1040

QUIT

MacBook Pro 15″, macOS 11.7

Posted on Jan 4, 2023 5:54 PM

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2 replies

Jan 4, 2023 7:20 PM in response to BobTheFisherman

Thanks Bob - fixed now (FWIW using an app password).


Strangely the smtp configuration had "lost" the (previously entered) username (email address) which probably explains the "*" in the session log! I assume this might be a side effect of having the cancel-response outcome.


After entering it again the MCD status went green - woo hoo !!


Happy casting.

Big Sur smtpclient.apple connection to smtp.gmail.com reports failure on Mail Connection Doctor

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