Problems with incorrect spam attribution are nothing new. For years, customers of mine who use Bluewin have had difficulties receiving e-mails. For incomprehensible reasons, personal and business messages did not arrive or ended up in the spam folder.
Bluewin’s support was able to explain some of the reasons. After all, at Bluewin you can actually reach the support and get answers. In the case of larger companies, such as Google or Microsoft, there is little chance of receiving competent responses. Unfortunately, as of the writing of this article, the spam filter situation at Bluewin has not improved. In the last few months, normal business messages from my normal Swiss mail account have not reached some customers or ended up in spam.
Emails are usually easy to test. I use the mail tester for this: https://www.mail-tester.com/
You send a message to a mailtester address and receive an evaluation of the message according to usual criteria. This way I can ensure that messages from me and my customers are well rated and never end up in spam with most recipients. Bluewin has its own rules and no testing option (reason: “a testing option would help spammers bypass the filters”).
Upon inquiry, I learned that my mails contain images that come from a Google server and have attached PDFs containing URL shorteners. I’ve been using GMail for sending for over two decades without any issues. GMail appends my signature, my picture in it is consequently delivered by Google – unfortunately a spam criterion for Bluewin.
I have also been using Google’s URL shortener for many years, as a simple link to my customer profiles. Without Shortener, the links would be very long and ugly, I don’t want to put my recipients through that. I also find it strange that Bluewin scans my business PDFs and judges them against such questionable criteria. (For URL shortening, meanwhile I use Joturl: https://joturl.com/)
In short: If you want to have as few spam messages as possible in your inbox, Bluewin may be a good solution. But be aware that you will then also have to fish a high proportion of reputable messages out of your spam folder.
Most hosters (including the ones I use for mailboxes) allow you to adjust the sensitivity of the spam filter. This is how a good compromise can be found. In addition, your own mails can be assessed reasonably reliably with mail testers and improvements are usually easily possible.
In the future, I will warn my customers against using Bluewin’s e-mail addresses and, as far as possible, will not send to such addresses. And in the case of important messages, ask Bluewin users to check spam in a safe way.
As much as I like to use and support Swiss providers, Bluewin’s spam filter overshoots the mark. Unfortunately not recommended.
What could help in the long run: If you use Bluewin and are affected by this problem, contact Bluewin. If enough messages arrive there, the filters may be corrected at some point.