linux - ive got dkim=neutral (bad version) header.i with gmail and dkim=fail (unknown key type) with yahoo

I'm having external ip and ubuntu server with
exim4.71 and bind9. I'm trying to set valid dkim entry to send mail for gmail

Here are my configuration files:
bind9:

_domainkey.example.com.       IN      TXT     "o=-;"

mail._domainkey.example.com.  IN      TXT     "v=DKIM1;k=rsa-sha256;p=MHwwDQYJKoZIhvcNAQEBBQADawAwaAJhAMDO8xXc3fMjQnWs6ejxTsrMa4xvb0470b2wCIbx1/790huhBr1386mkvvzeTpDDwkFmOZWXnJLw+Qeh4p/rkNQ7AVCk2uZQ+Kwy+jxM17QdZaDxSY9U1HYUFXC8BKAUYwIDAQAB"

I've got this results from check-auth@verifier.port25.com

==========================================================
Summary of Results
==========================================================
SPF check:          pass
DomainKeys check:   neutral

DKIM check:         pass
Sender-ID check:    pass
SpamAssassin check: ham

Any idea what the problem is?

from yahoo:

from=example.com; dkim=fail (unknown key type)

ive change k=rsa-sha256 to just k=rsa and now

from=example.com; dkim=pass (ok)

This also helped with gmail :)

Solution:

v=DKIM1;k=rsa-sha256;p=... --> v=DKIM1;k=rsa;p=....

Question solved

Answer

Solution:
change dkim field in BIND9 zone:
from v=DKIM1;k=rsa-sha256;p=... to --> v=DKIM1;k=rsa;p=....
rsa-sha256 or rsa-sha1 doesnt work for me :(