Hello,
Oh no problem, and thank for correcting it. As for you HTTPS connection. I have not used Certbot, mainly because our Graylog servers are internal at the moment. From what I can see this looks like a configuration issue, maybe on the cert part but im not 100% sure.
What I would do is check if your IPADDRESS has a reverse lookup in your DNS entry.
Second make sure the certs have a FQDN. For example when I created my self-signed certs I use FQDN for everything.
keytool -genkey -alias FQDN -keyalg RSA -validity 365 -keystore keystore.jks
keytool -import -trustcacerts -file graylog-certificate.pem -alias FQDN -keystore /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.144-0.b01.el7_4.x86_64/jre/lib/security/cacerts
Using these directions from Graylog Doc’s
Creating a self-signed private key/certificate
You will see there has to be alt names, and one being FQDN;
[alt_names]
IP.1 = 203.0.113.42
DNS.1 = graylog.example.com
Check your certs if you havent already.
And last check to see if you your Graylog server has access to Java keystore.
Here is my lab GL server config file I use this with TCP/TLS INPUT and HTTPS. Some settings might not work for your environment, may have to adjust it to your needs.
MY_GL_CONFIG
[root@graylog graylog_user]# grep -v "^#\|^$" /etc/graylog/server/server.conf | sed -e "s/#.*$//g"
is_master = true
node_id_file = /etc/graylog/server/node-id
password_secret =epOqmLi7r7CdZxl76QOQxr8bRUPYstNdcBuajsaSNfG5bkXXFxyHAAsdgmCfyHhSKlKXjMQG9ojc0bn22EBT17elgGTUJgbD
root_password_sha2 =272c3ac6b26a795a4244d8d2caf1d19a072fbc1c88d497ba1df7fef0a4171ea6
root_email = "greg.smith@domain.com"
root_timezone = America/Chicago
bin_dir = /usr/share/graylog-server/bin
data_dir = /var/lib/graylog-server
plugin_dir = /usr/share/graylog-server/plugin
http_bind_address = graylog.domain.net:9000
http_publish_uri = https://graylog.domain.net:9000/
http_enable_cors = true
http_enable_tls = true
http_tls_cert_file = /etc/ssl/certs/graylog/graylog-certificate.pem
http_tls_key_file = /etc/ssl/certs/graylog/graylog-key.pem
http_tls_key_password = secret
elasticsearch_hosts = http://8.8.8.8:9200
rotation_strategy = count
elasticsearch_max_docs_per_index = 20000000
elasticsearch_max_number_of_indices = 20
retention_strategy = delete
elasticsearch_shards = 4
elasticsearch_replicas = 0
elasticsearch_index_prefix = graylog
allow_leading_wildcard_searches = true
allow_highlighting = false
elasticsearch_analyzer = standard
elasticsearch_index_optimization_timeout = 1h
output_batch_size = 5000
output_flush_interval = 1
output_fault_count_threshold = 5
output_fault_penalty_seconds = 30
processbuffer_processors = 6
outputbuffer_processors = 2
processor_wait_strategy = blocking
ring_size = 65536
inputbuffer_ring_size = 65536
inputbuffer_processors = 3
inputbuffer_wait_strategy = blocking
message_journal_enabled = true
message_journal_dir = /var/lib/graylog-server/journal
message_journal_max_size = 12gb
lb_recognition_period_seconds = 3
mongodb_uri = mongodb://mongo_admin:password123@localhost:27017/graylog
mongodb_max_connections = 1000
mongodb_threads_allowed_to_block_multiplier = 5
transport_email_enabled = true
transport_email_hostname = localhost
tansport_email_port = 25
transport_email_subject_prefix = [graylog]
transport_email_from_email = root@domain.net
transport_email_web_interface_url = https://graylog.domain.net:9000
http_connect_timeout = 10s
proxied_requests_thread_pool_size = 32
[root@graylog graylog_user]#
EDIT: And the link @aaronsachs posted is a must to your configuration file.
To be honest, I dont to worried about Chrome trusting my certs inside my lab 
Hope that helps
