dkim=temperror (no key for signature)

[spoollka]

Hello, everyone!
There is something happens, i can't figure out what exactly.
We have Mail Gateway 8.0.11, we use it to send service alerts only, and we want to use DKIM sign.
DNS-records is fine


DMARC PASS
SPF PASS

PMG Settings:



But there is an error (for gmail.com):
dkim=temperror (no key for signature) header.i=@som.chat header.s=chat header.b="Pq/dDahP";

I`ve tryed to change Selector, restart\reboot, /etc/pmg/dkim/chat.private seems fine.
What should i check, any thoughts would be welcome