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Message could not be sent. Mailer Error: SMTP Error: Could not authenticate. · Issue #1943 · PHPMailer/PHPMailer · GitHub
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SMTP Error: Could not connect to SMTP host. · Issue #1318 · PHPMailer/PHPMailer · GitHub
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SMTP Error: Could not connect to SMTP host · Issue #1176 · PHPMailer/PHPMailer · GitHub
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![JENKINS-58813] Cannot send Email notification over office365 smtp with starttls has no effect - Jenkins Jira](https://issues.jenkins.io/secure/attachment/51086/jenkinsError.png "JENKINS-58813] Cannot send Email notification over office365 smtp with starttls has no effect - Jenkins Jira")
JENKINS-58813] Cannot send Email notification over office365 smtp with starttls has no effect - Jenkins Jira
![php - How to resolve SMTP could not connect error? [post STARTTLS problem] - Stack Overflow](https://i.stack.imgur.com/hDgcl.png "php - How to resolve SMTP could not connect error? [post STARTTLS problem] - Stack Overflow")