Sent vs Opens for t-online.de

Blocks from t-online.de

No blocks during specified time frame

Bounces from t-online.de

Explanation of bounce codes

Methodology

Send and open statistics are updated daily. Bounces and blocks are updated in real-time. Every day, open statistics are updated for the last 14 days. Generally, you'll notice an increase of an open rate for a domain for a day over the course of 14 days, since not all open events occur the same day an email is sent. That means that open rate data is tied to the actual emails sent on a particular day.

Bounce and block codes are the codes as returned by the remote SMTP server after having been de-personalized. Meaning, unique identifiers present in SMTP codes are removed so that SMTP responses can be grouped for analysis. In certain cases, such as when the email is being relayed through an intermediary SMTP server, the remote SMTP server may not be the same as the MX record for the domain. SMTP codes are categorized as "bounces" vs "blocks" by internal human review. Bounces generally indicate an invalid email address. Blocks generally indicate a rejection of the email message but a valid email address.