Change SMTP server

I am on Drupal 7.55 and we changed SMTP server for sending emails. I changed the SMTP server IP under admin/config/system/smtp (SMTP Authentication Support), but am not getting any e-mails. I added Mail debugger and Mail Logger modules to check if e-mails are being sent and I see a lot of entries under admin/reports/mail-logger for the “New release(s) available for” e-mail messages, but doesn’t really give any error message. Under admin/reports/dblog, I do get error messages for the emails being sent, but only says “Error sending e-mail”. Not very descriptive.

Is there a way to figure out why I am not being able to send emails or at least get a more descriptive error message?

I have telneted from the server to the SMTP server and have been able to connect and even send an email sucesfully.

I am using a Windows 2008 R2 server using Acquia Drupal 7.

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