When sending invitations or reminders for your survey you have two choices:
1.) Using our mail server
If you are using the LimeSurvey Cloud mail server, all your emails will have the sender address "noreply@limesurvey.org". However, these emails will have a Reply-to header with your email address. So in case someone tries to reply they will write to you directly.
Although this method is set up very quickly (just enter global settings and set 'LimeSurvey' as your preferred mail type) it has one downside: If an email cannot be transmitted to the email receiver and bounces back, then you won't get any notifications whatsoever.
If spam is suspected your account will be locked. Make sure that you have the general consent of people you want to send invitations to.
2.) Using your own SMTP server
This method has the advantage that you can send all email invitations and reminders using your own sender address and you will get bounced emails back. Most email and hosting providers offer SMTP to send emails. The only thing for you to find out is how to send an email via that SMTP - by figuring out the following details:
Email address (which is allowed to send using that server)
SMTP user name (in many cases this is the same as the email address)
SMTP host name
Password
Does your SMTP require an SSL or TLS connection? If yes, also find out which port it is.
Then enter the global settings dialog in your LimeSurvey installation and go to the email tab - enter the required data. If your SMTP server is using a special port, then attach it to the host name with a colon. For example, if your host name is 'smtp.server.net' and the port is 143, then write 'smtp.server.net:143' as host name. For security reasons we currently only allow the following ports numbers: 110, 143, 587, 993 and 995.
After you save the new settings make sure that you enter that same valid email address in the survey settings of your survey.
Now it should all be running as expected.
A note to email server administrators:
LimeSurvey will initialize the SMTP connection from the IP address of your LimeSurvey installation. Just ping the URL of the LimeSurvey installation to find out which one it is. In case you have your SMTP server locked down you will need to add this IP address as an exception to your SMTP configuration/firewall.