Mario,
Most likely cause of this error is that your SMTP server is rejecting the email generated by SynaMan. Here is how public links work:
- When a user generates a public link, SynaMan composes an email with the link
- This email is sent to the SMTP server you have configured in SynaMan
- Depending upon the recipient of the email, the SMTP server may reject the message.
Since it is working for your domain but not foreign domains (gmail.com or outlook.com), your SMTP server is not accepting messages for relaying. Typically, when you specify a user id/password in the SMTP configuration, the server should allow relaying.
Try the following test:
- Download Email Sender program from https://xeams.com/email-sender.htm
- Extract the downloaded zipped file into the same folder where SynaMan is installed. For example: C:\SynaMan
- Double click the EmailSender.bat file to run and then compose a test email
- Specify the same values that you're using in your SynaMan in the Email Sender utility.
- Look at the SMTP Log after clicking send
This will give you the exact reason why your SMTP server rejected the email.