How to reduce the bitcoin transaction fee in cert-issuer from 60000 satoshis to 6000

We would like to make it 6000 satoshis
We tried adding tx_fee = 0.00006 in the conf.ini of cert-issuer. But it didn’t work
Any suggestions?

Looks like it takes the max of recommended fee and satoshis per byte * size.

So to simplify this to what goes in your conf.ini: