getting ssl_ctx client key error from unbound-control

Does anyone have a clue why am I getting this error?

$ unbound-control verbosity 5
error: Error setting up SSL_CTX client key and cert
548001674288:error:0200100D:system library:fopen:Permission denied:../crypto/bio/bss_file.c:290:fopen('/etc/unbound/unbound_control.pem','r')
548001674288:error:20074002:BIO routines:file_ctrl:system lib:../crypto/bio/bss_file.c:292:
548001674288:error:140DC002:SSL routines:use_certificate_chain_file:system lib:../ssl/ssl_rsa.c:615:

Best approach might be to ask unbound related questions in the unbound mailing list