Even if emails are successfully sent via your web hosting, it can happen that they end up in the spam folder of the recipient or are not delivered at all.
The reason for this is the spam filters of the recipient's mail servers: they evaluate each message using a point system (spam score). If a certain value is exceeded, the email ends up in spam.
It is important to distinguish between regular emails (e.g., business correspondence, 1:1 communication) and newsletters or mass emails.
1. Regular emails (1:1 communication)
Common reasons for being marked as spam
Missing authentication
Without correctly set SPF, DKIM, and DMARC records, the recipient server cannot verify the authenticity of the email.Shared sender IP
All customers send via the same sender IP. If another customer is flagged, the reputation of all is affected.Content issues
– Subject or body contains spam trigger words (“free”, “100% free”, “buy now”).
– Too many external links or suspicious attachments.Technical factors
– Sender address is very different from the sender stored in DNS.
– Large attachments or unusual formats.
Tips for better deliverability
Correctly enter SPF/DKIM/DMARC in DNS.
Use a reputable subject line (no caps lock, no sensational wording).
Keep the sender address clear and consistent (e.g., always “info@your-domain.at”).
Do not use suspicious keywords or unnecessarily many links.
Only send attachments in common formats (PDF, JPG, DOCX).
2. Newsletters and mass mailing
Special aspects in web hosting
Sending limits: The limits are set to protect against spam and are not intended for marketing emails. You can find them here: How many emails can/may I send (email limit)?
Spam filter sensitivity: Many identical emails sent in a short time are quickly flagged as mass mail.
Reputation: Web hosting servers share the IP. Even a few complaints (spam reports) can massively impair deliverability.
Missing features: No bounce handling, no statistics, no automatic unsubscribe – all features that professional newsletter services offer.
Typical spam traps in newsletters
Subject lines
– ALL IN CAPS
– Exaggerated urgency (“Only today!!!”, “BUY NOW”)
– Emojis or many special charactersDesign
– Only images without text → spam filters rate this negatively.
– Flashy colors, large fonts or blinking elements.
– Missing unsubscribe link or legal notice.Content
– Spam words like “free”, “immediately”, “100% free”.
– Repeated links or tracking URLs.
Best practices
Send only to small recipient groups.
Keep recipient lists clean → only contacts with double opt-in.
Keep the subject short & factual, no caps lock or emojis.
Mix text and images so the email remains understandable even without images.
Always include an unsubscribe link and legal notice.