Why is the DKIM signature not valid?

Question

Email

I send an email to mail-tester, his response is:

Подпись DKIM Вашего письма это:

  v=1;
  a=rsa-sha256;
  c=relaxed/relaxed;
  d=domain.ru;
  s=default;
  t=14108816;
  bh=puRuWobORLDxEnv4krosO79MRKSkDkD+sI=;
  h=To:Subject:From:Date;
  b=xxQcXALK4tC2LMKdfg8OvZYPXA/JoCjmR7RYGYdP3UbTj2/RXNRm97Pzh+CJU1Cvg9+5t2wsLTO7udsdfdsf44436CDlFuzJHLBFONp5sMBc+zmWdR3fz5MenMwhUuggXNntdsf4KP5xuBZLnQU=
Ваш открытый ключ:

"v=dkim1;
k=rsa;"
"p=migfma0gcsqgsidqaa4gnadcbiqkbgqcydv/48vv5fs4mnq1fx7jnpbkyv0rt5vr+qglwcig9eb0ewacopbywxt5lu2sfslwdsfdsytvwnxjfet/wcvs3yvzdrqthblz6al7wazfunn0o5hqjmbofknyicdsfwtkcphimdsdfp8dor3fdsws0cqsvjccwzkycjgpx/lsazqidaqab"
Ваша DKIM подпись не действительна

Answer 1

Where are you sending? Does the mail go directly or through someone (Google, Yandex, Mailru)? Let's try to figure it out... Just verified one of my domains by sending it to [email protected] Here is the answer:

========================================================== 
Summary of Results 
========================================================== 
SPF check: pass 
DomainKeys check: neutral 
DKIM check: pass 
Sender-ID check: pass 
SpamAssassin check: ham