remote control failed ssl crypto error

Few weeks back I installed unbound on my arm64 rockpi running ubuntu

Linux rockpi 4.4.154-110-rockchip-gcef30e88a9f5 #1 SMP Mon Jun 22 07:37:10 UTC 2020 aarch64 aarch64 aarch64 GNU/Linux

the version of unbound is 1.6.7
the service starts but continues to error

Aug 18 19:47:34 rockpi systemd[1]: Starting Unbound DNS server…

Aug 18 19:47:34 rockpi package-helper[8886]: /var/lib/unbound/root.key has content

Aug 18 19:47:34 rockpi package-helper[8886]: success: the anchor is ok

Aug 18 19:47:34 rockpi unbound[8890]: [8890:0] info: start of service (unbound 1.6.7).

Aug 18 19:47:34 rockpi systemd[1]: Started Unbound DNS server.

Aug 18 19:47:45 rockpi unbound[8890]: [8890:0] error: remote control failed ssl crypto error:14094412:SSL routines:ssl3_read_bytes:sslv3 alert bad certificate

Aug 18 19:47:49 rockpi unbound[8890]: [8890:0] error: remote control failed ssl crypto error:1408F09C:SSL routines:ssl3_get_record:http request

Aug 18 19:48:00 rockpi unbound[8890]: [8890:0] error: remote control failed ssl crypto error:14094412:SSL routines:ssl3_read_bytes:sslv3 alert bad certificate

please help

Best Regards,