Level 1: Cadet

Can't send Gmail - SMTP error

Just moved today to Telstra Wireless Internet, previously on Optus Wireless internet. Outlook client worked fine, now on Telstra can receive emails but not send. Tried

  • Gmail SMTP port (TLS): 587.
  • Gmail SMTP port (SSL): 465.
  • Gmail SMTP port 25

None will let me send emails. Don't know what port Telstra is blocking??


Gmail account using Outlook client for Windows.


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Level 24: Supreme Being
Level 24: Supreme Being

Re: Can't send Gmail - SMTP error

Telstra and most ISPs blocks port 25 to other than there own mail servers. The other ports should work Okay.


There could be a problem with outlook and Gmail. Gmail used to work via outlook on my PC but no longer works. It still works using windows  mail on the same PC.

Level 23: Superhero

Re: Can't send Gmail - SMTP error

Gmail considers many versions of Outlook as not secure. You can override this in Gmail by opening on webmail and going into secitity settings. It still every now and then reminds that its not secure.

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I'm not a Telstra employee.
50 + years exp. in radio comms., eg mobile phones since 1963, two-way radios, base stations, antennas & pagers. Expert in current Telstra Go repeaters & smart antennas.
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Level 24: Supreme Being
Level 24: Supreme Being

Re: Can't send Gmail - SMTP error

I have already overridden security settings to use less secure apps and still doesn't work. Google considers everything except its own apps as less secure.

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