Mike. You are right.
I forgot to see with the hosts_require_tls enabled for this host.
So... There are a strange behavior...
I have the correct user, the correct password and try again using the TLS.
And... On debug log... I had the same auth fail problem:
SMTP>> STARTTLSwaiting for data on socketread response data: size=29 SMTP<< 220 2.0.0 SMTP server readysetting SSL CTX options: 0x1000000Diffie-Hellman initialized from default with 2048-bit primeInitialized TLSCalling SSL_connectSSL info: before/connect initializationSSL info: before/connect initializationSSL info: SSLv2/v3 write client hello ASSL info: SSLv3 read server hello ASSL info: SSLv3 read server certificate ASSL info: SSLv3 read server done ASSL info: SSLv3 write client key exchange ASSL info: SSLv3 write change cipher spec ASSL info: SSLv3 write finished ASSL info: SSLv3 flush dataSSL info: SSLv3 read finished ASSL info: SSL negotiation finished successfullySSL info: SSL negotiation finished successfullySSL_connect succeededCipher: TLSv1:AES128-SHA:128 SMTP>> EHLO host.mylocalsmtp.com.brtls_do_write(0xbf9ff3fc, 25)SSL_write(SSL, 0xbf9ff3fc, 25)outbytes=25 error=0waiting for data on socketCalling SSL_read(0x8143148, 0xbf9fd3fc, 4096)read response data: size=176 SMTP<< 250-pod51028.outlook.com Hello [189.74.52.32] 250-SIZE 36700160 250-PIPELINING 250-DSN 250-ENHANCEDSTATUSCODES 250-AUTH LOGIN 250-8BITMIME 250-BINARYMIME 250 CHUNKING207.46.4.237 in hosts_avoid_pipelining? no (option unset)using PIPELININGgethostbyname looked up these IP addresses: name=pod51028.outlook.com address=207.46.4.237207.46.4.237 in hosts_require_auth? yes (matched "pod51028.outlook.com")scanning authentication mechanismsskipping server_plain authenticator: not configured as a clientskipping server_login authenticator: not configured as a client SMTP>> AUTH LOGINtls_do_write(0xbf9ff3fc, 12)SSL_write(SSL, 0xbf9ff3fc, 12)outbytes=12 error=0waiting for data on socketCalling SSL_read(0x8143148, 0xbf9fd3fc, 4096)read response data: size=18 SMTP<< 334 VXNlcm5hbWU6search_open: lsearch "/opt/addons/etc/exim/client_credentials.conf"search_find: file="/opt/addons/etc/exim/client_credentials.conf" key="emexis_redirect_delivery_5" partial=-1 affix=NULL starflags=0LRU list: 5/opt/addons/etc/exim/client_credentials.conf Endinternal_search_find: file="/opt/addons/etc/exim/client_credentials.conf" type=lsearch key="redirect_delivery_5"file lookup required for redirect_delivery_5 in /opt/addons/etc/exim/client_credentials.conflookup yielded: user="xxx@domain" pass="mypass" SMTP>> ****************************tls_do_write(0xbf9ff3fc, 30)SSL_write(SSL, 0xbf9ff3fc, 30)outbytes=30 error=0waiting for data on socketCalling SSL_read(0x8143148, 0xbf9fd3fc, 4096)read response data: size=18 SMTP<< 334 UGFzc3dvcmQ6search_open: lsearch "/opt/addons/etc/exim/client_credentials.conf" cached opensearch_find: file="/opt/addons/etc/exim/client_credentials.conf" key="emexis_redirect_delivery_5" partial=-1 affix=NULL starflags=0LRU list: 5/opt/addons/etc/exim/client_credentials.conf Endinternal_search_find: file="/opt/addons/etc/exim/brc_client_credentials.conf" type=lsearch key="redirect_delivery_5"cached data used for lookup of redirect_delivery_5 in /opt/addons/etc/exim/client_credentials.conflookup yielded: user="xxx@domain" pass="mypass" SMTP>> ************tls_do_write(0xbf9ff3fc, 14)SSL_write(SSL, 0xbf9ff3fc, 14)outbytes=14 error=0waiting for data on socketCalling SSL_read(0x8143148, 0xbf9fd3fc, 4096)read response data: size=39 SMTP<< 535 5.7.3 Authentication unsuccessful