Kibana SSL error with opendistro 1.11

Elasticsearch OSS 7.9.1 with opendisro_security_plugin
Kibana OSS 7.9.1 with opendistro_security plugin 1.11
Whenever a client connects to Kibana, a message appears on Its console (stdout):
server error [21:01:48.908] [error][client][connection] Error: 4248:error:140944E7:SSL routines:ssl3_read_bytes:reason(1255):c:\ws\deps\openssl\openssl\ssl\record\rec_layer_s3.c:1544:SSL alert number 255

when you access kibana, does your browser say the certificate is valid or invalid?