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Why will Thunderbird not 'send' tells me it needs a STARTTLS command

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When I try to send a message from either of my addresses, I get the following message

"An error occurred while sending mail. The mail server responded: 5.7.0 Must issue a STARTTLS command first. Please verify that your email address is correct in your Mail preferences and try again."

When I try to send a message from either of my addresses, I get the following message "An error occurred while sending mail. The mail server responded: 5.7.0 Must issue a STARTTLS command first. Please verify that your email address is correct in your Mail preferences and try again."

Chosen solution

Go to your server settings and change Connection Security to STARTTLS. It sounds like your provider finally entered the present day in email servers.

Tools-Account Settings-Server Settings for inbound server.

Tools-Account Settings-Outgoing Server (SMTP) for outbound server.

No menu bar with Tools? Press the alt key.

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Chosen Solution

Go to your server settings and change Connection Security to STARTTLS. It sounds like your provider finally entered the present day in email servers.

Tools-Account Settings-Server Settings for inbound server.

Tools-Account Settings-Outgoing Server (SMTP) for outbound server.

No menu bar with Tools? Press the alt key.