Answering to a message via email does not work

[Stortebecker]

Hi!
We normally do not log in to the website for messaging, but use email. This worked fine until the 21st of May. However, on the 17th of June, an email we sent did not reach the recipient and all emails we sent since then did not arrive. Messaging on the site itself works fine, though.
What could be the problem? Does the sending email address matter? Can it be a problem with the automatic generation of the email-tags? Here is one example of such a tag from an email that did not get to the recipient: [mid.2791776.134959.rQH1dhPmHfKKpYo+wkBHfCZcBb8=].
Cheers, Flo

[Stortebecker]

Other tag examples of emails that did not reach the addressant. None of the emails were registered in our profile in any way.

Warmshowers Messages
messages+mid.3195941.134959.VFAS2s2gChug6CTHidSKEDZG5Ag=@reply.warmshowers.org

Warmshowers Messages
messages+mid.3196252.134959.gz1l6MzfjpKhcTvAR5CJsnqIHhg=@reply.warmshowers.org

Warmshowers Messages
messages+mid.3194977.134959.mu1TjhcPa/[email protected]

[greenorca]

We have had the same issue.

[adrielklein]

I'm having the same issue. Also I see html tags in the text of the emails I get when people send me messages.