Next day now, and I still cannot get past the internal server error. I did modify several index templates per the workaround, but all I get is the internal server error now.
I do see these in the Kibana logs:
{"type":"log","@timestamp":"2021-02-17T07:35:38-08:00","tags":["error","plugins","fleet"],"pid":806,"message":"Request Timeout after 30000ms"}
{"type":"log","@timestamp":"2021-02-17T07:35:38-08:00","tags":["error","http"],"pid":806,"message":"Error: options.statusCode is expected to be set. given options: undefined
at Object.customError (/usr/share/kibana/src/core/server/http/router/response.js:136:13)
at defaultIngestErrorHandler (/usr/share/kibana/x-pack/plugins/fleet/server/errors/handlers.js:117:19)
at FleetSetupHandler (/usr/share/kibana/x-pack/plugins/fleet/server/routes/setup/handlers.js:111:50)
at runMicrotasks (<anonymous>)
at processTicksAndRejections (internal/process/task_queues.js:93:5)
at Router.handle (/usr/share/kibana/src/core/server/http/router/router.js:163:30)
at handler (/usr/share/kibana/src/core/server/http/router/router.js:124:50)
at module.exports.internals.Manager.execute (/usr/share/kibana/node_modules/@hapi/hapi/lib/toolkit.js:45:28)
at Object.internals.handler (/usr/share/kibana/node_modules/@hapi/hapi/lib/handler.js:46:20)
at exports.execute (/usr/share/kibana/node_modules/@hapi/hapi/lib/handler.js:31:20)
at Request._lifecycle (/usr/share/kibana/node_modules/@hapi/hapi/lib/request.js:312:32)
at Request._execute (/usr/share/kibana/node_modules/@hapi/hapi/lib/request.js:221:9)"}
{"type":"error","@timestamp":"2021-02-17T07:34:58-08:00","tags":[],"pid":806,"level":"error","error":{"message":"Internal Server Error","name":"Error","stack":"Error: Internal Server Error
at HapiResponseAdapter.toInternalError (/usr/share/kibana/src/core/server/http/router/response_adapter.js:58:19)
at Router.handle (/usr/share/kibana/src/core/server/http/router/router.js:177:34)
at runMicrotasks (<anonymous>)
at processTicksAndRejections (internal/process/task_queues.js:93:5)
at handler (/usr/share/kibana/src/core/server/http/router/router.js:124:50)
at module.exports.internals.Manager.execute (/usr/share/kibana/node_modules/@hapi/hapi/lib/toolkit.js:45:28)
at Object.internals.handler (/usr/share/kibana/node_modules/@hapi/hapi/lib/handler.js:46:20)
at exports.execute (/usr/share/kibana/node_modules/@hapi/hapi/lib/handler.js:31:20)
at Request._lifecycle (/usr/share/kibana/node_modules/@hapi/hapi/lib/request.js:312:32)
at Request._execute (/usr/share/kibana/node_modules/@hapi/hapi/lib/request.js:221:9)"},"url":"https://kb.contoso.com/api/fleet/setup","message":"Internal Server Error"}
{"type":"response","@timestamp":"2021-02-17T07:34:58-08:00","tags":["access:fleet-read"],"pid":806,"method":"post","statusCode":500,"req":{"url":"/api/fleet/setup","method":"post","headers":{"host":"kb.contoso.com","user-agent":"Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:85.0) Gecko/20100101 Firefox/85.0","accept":"*/*","accept-language":"en-US,en;q=0.5","accept-encoding":"gzip, deflate, br","referer":"https://kb.contoso.com/s/space-name/app/fleet","content-type":"application/json","kbn-version":"7.11.0","origin":"https://kb.contoso.com","connection":"keep-alive","content-length":"0"},"remoteAddress":"192.168.1.100","userAgent":"Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:85.0) Gecko/20100101 Firefox/85.0","referer":"https://kb.contoso.com/s/space-name/app/fleet"},"res":{"statusCode":500,"responseTime":40519,"contentLength":9},"message":"POST /api/fleet/setup 500 40519ms - 9.0B"}