Email Sending Issue (Custom SMTP Server)

I have a custom SMTP server set up in Manager. However, when sending emails I encounter the below error. Sometimes the emails send without this error and then sometimes I receive the error and I hit send again and the email goes through. Does anyone else have this same issue? I do not understand enough of computer technical language to know what the error message is trying to tell me.

This error message appears randomly and even after I have just successfully sent an email. It does not matter whether its invoices, payslips, statements etc, they all have this error randomly appear. Any suggestions on where the issue may lie? It ultimately doesn’t stop emails going through but is just an inconvenience as sometimes you will have to hit send multiple times before it will send.

Thanks for your help.

That’s weird but it does look like something wrong with SMTP server rather than with Manager.

Especially if these errors are random because the email Manager composes is always the same while the SMTP server is returning inconsistent responses.

What if you try port 25 without SSL option checked.

@lubos Thanks for the reply. I updated the settings as above and still received the error message. I will follow this up with my service provider as the issue is most likely coming from that side.

I’m pretty sure that is the case too but unless they are specializing in SMTP, they will be reluctant to troubleshoot the issue. I’d suggest to change SMTP provider. I have a good experience with which has a free plan (first 10,000 sent emails are free)

@lubos I have my service provider troubleshooting my issue with my custom SMTP server and they have requested to confirm the IP address of the server that Manager is using. Is this something that you are able to provide?

If it’s cloud edition, then IP address being used to send email is IP address of your subdomain.

I am using the desktop version 19.5.75. How would I find the relevant IP address that Manager uses to send emails?

If you are using desktop edition, then it’s IP address of your computer/intranet. Type into Google What is my IP address


Apologies lubos for the continuing thread.

My SMTP provider has asked the following question regarding my error message. Do you have any further suggestions regarding this error?

“The error is very vague and does not even have an error code so it’s hard to determine what this intermittent failure means. We have no issues on the server included. Could you ask dev of the software what email error code this is related too, or more detail on how this would happen.”

@lubos would you happen to have any more detail on the error code for this email error that I could provide my SMTP? Thanks