Invitation Mailings got sent 15-30 minutes later to some participants

Question

I am running a study with 3 daily measurement points for 10 days and the past days everything worked fine. This afternoon, the invitation emails were supposed to be sent at 13.00 (I also checked this under "Mailings"). However, most participants only received the email between 13.15 and 13.35. I want to make sure that this will not happen again for the next measurement points. Do you know what the issue could be? Was there a server issue?

Comments

Please send me one or two email addresses that have been affected to info@soscisurvey.de, and also include the URL of your project in the email.

There are several possibilities that delay email delivery, but based on the logfiles I should be able to decide if they are on our server's side or on the recipient side.

In general, please note that there is no guarantee that emails are delivered within a short time. Multiple processes may cause delays, for example for spam filtering (greylisting) or due to high load anywhere along the route. Email simply was not designed for real-time transmissions...

Answer 1

After checking the logfiles (details sent via email) we found no delay on behalf our servers. The emails were handed over to the receiving mailserver within 1 minute after the scheduled sending time.