Auth failures when attempting to register PMM client

We’ve recently installed an upgrade from PMM to PMM 3.8.0 and I’m having issues registering any clients with the new server. No matter what I put for the auth string in “pmm-admin config” it fails with:

[root@dv1medpglabdb1 mrolfs]# pmm-admin config --server-insecure-tls --server-url=https://:PASSWORD@:443
Checking local pmm-agent status…
pmm-agent is running.
Registering pmm-agent on PMM Server…
Failed to register pmm-agent on PMM Server: Internal server error.
Please check username and password.

  • I can telnet to the server on 443
  • I can log into the server web interface
  • It fails no matter what user I put, and I’ve tested all user logins from the UI
  • It also fails if I use a service account and put "https://service_token:glsa_@:443
  • Running it in debug I get this output which from what I can tell basically says the same thing as “auth failure” with an HTTP 401 returned (I’ll include that output down below)
  • I’m also having issues in the UI saving some specific settings, especially the “Check for updates” switch which nets me “Updates are configured via PMM_ENABLE_UPDATES environment variable” and “Request failed with status code 400” errors when I attempt to save

HALP ME PERCONA WAN KENOBI YOU’RE MY ONLY HOPE

Debug output:

[root@dv1medpglabdb1 mrolfs]# pmm-admin config --server-insecure-tls --server-url=https://<USERNAME>:<PASSWORD>@<SERVER ADDRESS>:443 --debug
DEBUG 2026-08-20 16:00:26.734779871Z: Running: pmm-agent --server-address=<SERVER ADDRESS>:443 --server-username=<USERNAME> --server-password=<PASSWORD> --listen-port=7777 --server-insecure-tls --log-level=warn --debug --log-lines-count=1024 setup --metrics-mode=auto <LOCAL IP> generic <LOCAL SERVER HOSTNAME>
DEBUG 2026-08-20 16:00:33.018239105Z: Result: &commands.configResult{Warning:"", Output:"Checking local pmm-agent status...\npmm-agent is running.\nRegistering pmm-agent on PMM Server...\nFailed to register pmm-agent on PMM Server: Internal server error.\nPlease check username and password."}
DEBUG 2026-08-20 16:00:33.018898324Z: Error: &exec.ExitError{ProcessState:(*os.ProcessState)(0x3541f87ce018), Stderr:[]uint8{<HEX CODES THAT MADE THE POST FAIL WITH TOO MANY CHARACTERS}}
Checking local pmm-agent status...
pmm-agent is running.
Registering pmm-agent on PMM Server...
Failed to register pmm-agent on PMM Server: Internal server error.
Please check username and password.
DEBUG 2026-08-20 16:00:33.019207807Z: exit status 1, stderr:
time="2026-08-20T16:00:26.759+00:00" level=info msg="Temporary directory will default to /usr/local/percona/pmm/tmp" component=setup
time="2026-08-20T16:00:26.760+00:00" level=info msg="Nomad data directory will default to /usr/local/percona/pmm/data/nomad" component=setup
time="2026-08-20T16:00:26.760+00:00" level=info msg="Using /usr/local/percona/pmm/tools/pt-summary as a path to Percona Toolkit pt-summary" component=setup
time="2026-08-20T16:00:26.760+00:00" level=info msg="Using /usr/local/percona/pmm/tools/pt-pg-summary as a path to Percona Toolkit pt-pg-summary" component=setup
time="2026-08-20T16:00:26.760+00:00" level=info msg="Using /usr/local/percona/pmm/tools/pt-mongodb-summary as a path to Percona Toolkit pt-mongodb-summary" component=setup
time="2026-08-20T16:00:26.760+00:00" level=info msg="Using /usr/local/percona/pmm/tools/pt-mysql-summary as a path to Percona Toolkit pt-mysql-summary" component=setup
time="2026-08-20T16:00:26.760+00:00" level=info msg="Using /usr/local/percona/pmm/tools/nomad as a path to Nomad binary" component=setup
time="2026-08-20T16:00:26.760+00:00" level=info msg="Using /usr/local/percona/pmm/exporters/node_exporter as a path to node_exporter" component=setup
time="2026-08-20T16:00:26.760+00:00" level=info msg="Using /usr/local/percona/pmm/exporters/mongodb_exporter as a path to mongodb_exporter" component=setup
time="2026-08-20T16:00:26.760+00:00" level=info msg="Using /usr/local/percona/pmm/exporters/postgres_exporter as a path to postgres_exporter" component=setup
time="2026-08-20T16:00:26.760+00:00" level=info msg="Using /usr/local/percona/pmm/exporters/valkey_exporter as a path to valkey_exporter" component=setup
time="2026-08-20T16:00:26.760+00:00" level=info msg="Using /usr/local/percona/pmm/exporters/azure_exporter as a path to azure_exporter" component=setup
time="2026-08-20T16:00:26.760+00:00" level=info msg="Using /usr/local/percona/pmm/exporters/mysqld_exporter as a path to mysqld_exporter" component=setup
time="2026-08-20T16:00:26.760+00:00" level=info msg="Using /usr/local/percona/pmm/exporters/proxysql_exporter as a path to proxysql_exporter" component=setup
time="2026-08-20T16:00:26.760+00:00" level=info msg="Using /usr/local/percona/pmm/exporters/rds_exporter as a path to rds_exporter" component=setup
time="2026-08-20T16:00:26.760+00:00" level=info msg="Using /usr/local/percona/pmm/exporters/vmagent as a path to vmagent" component=setup
time="2026-08-20T16:00:26.761+00:00" level=debug msg="POST /local/Status HTTP/1.1\r\nHost: 127.0.0.1:7777\r\nUser-Agent: Go-http-client/1.1\r\nContent-Length: 3\r\nAccept: application/json\r\nContent-Type: application/json\r\nAccept-Encoding: gzip\r\n\r\n{}\n\n" component=setup
time="2026-08-20T16:00:26.776+00:00" level=debug msg="HTTP/1.1 200 OK\r\nContent-Length: 231\r\nContent-Type: application/json\r\nDate: Thu, 20 Aug 2026 16:00:26 GMT\r\nGrpc-Metadata-Content-Type: application/grpc\r\n\r\n{\n  \"agent_id\": \"\",\n  \"runs_on_node_id\": \"\",\n  \"node_name\": \"\",\n  \"server_info\": null,\n  \"agents_info\": [],\n  \"config_filepath\": \"/usr/local/percona/pmm/config/pmm-agent.yaml\",\n  \"agent_version\": \"3.8.0\",\n  \"connection_uptime\": 0\n}\n" component=setup
time="2026-08-20T16:00:26.777+00:00" level=debug msg="Status error: <nil>" component=setup
time="2026-08-20T16:00:26.777+00:00" level=debug msg="POST /v1/management/nodes HTTP/1.1\r\nHost: <SERVER ADDRESS>:443\r\nUser-Agent: Go-http-client/1.1\r\nContent-Length: 231\r\nAccept: application/json\r\nAuthorization: Basic Y2xpZW50LXJlZ2lzdGVyOnphcTEyd3N4Y2RlMzRyZnY=\r\nContent-Type: application/json\r\nAccept-Encoding: gzip\r\n\r\n{\"node_type\":\"NODE_TYPE_GENERIC_NODE\",\"node_name\":\"<LOCAL HOSTNAME>\",\"address\":\"<LOCAL IP>\",\"machine_id\":\"56da652e05d844cc8f589dadfab293c8\",\"distro\":\"linux\",\"metrics_mode\":\"METRICS_MODE_AUTO\",\"disable_collectors\":null}\n\n" component=setup
time="2026-08-20T16:00:33.015+00:00" level=debug msg="HTTP/1.1 401 Unauthorized\r\nContent-Length: 80\r\nConnection: keep-alive\r\nContent-Type: application/json\r\nDate: Thu, 20 Aug 2026 16:00:33 GMT\r\nStrict-Transport-Security: max-age=31536000; includeSubDomains\r\n\r\n{\"code\":13,\"error\":\"Internal server error.\",\"message\":\"Internal server error.\"}\n\n" component=setup
time="2026-08-20T16:00:33.015+00:00" level=debug msg="Register error: &management_service.RegisterNodeDefault{_statusCode:401, Payload:(*management_service.RegisterNodeDefaultBody)(0x2c2c4b8f72f0)}" component=setup