"Failed to get macro details" -error when trying to insert macro on any page

[G]

While editing a new or existing page I am sometimes unable to insert macros.

I type "{" to open the "search macro popup", but it fails:

Sometimes it works if I wait a few minutes and try again.

Web browser console output

Synchrony connected.
batch.js?frontend.editor.v4=true&gatekeeper-ui-v2=true&healthcheck-resources=true&hostenabled=true&locale=en-GB&onboarding-in-progress=true&user-logged-in=true&whisper-enabled=true:2351 

Autocompleter.Control - init : suggestionHtml = 
batch.js?frontend.editor.v4=true&gatekeeper-ui-v2=true&healthcheck-resources=true&hostenabled=true&locale=en-GB&onboarding-in-progress=true&user-logged-in=true&whisper-enabled=true:2994 

DEBUG: 23:38:50 Stoping entity synchronization confluence.autocomplete-plugin Object
batch.js?frontend.editor.v4=true&gatekeeper-ui-v2=true&healthcheck-resources=true&hostenabled=true&locale=en-GB&onboarding-in-progress=true&user-logged-in=true&whisper-enabled=true:2994 

DEBUG: 23:39:20 Auto recovery has been triggered confluence.autocomplete-plugin
batch.js?locale=en-GB:1980 

Error requesting macro browser metadata:
batch.js?locale=en-GB:1980 

[object Object]

Server logs

This seems relevant:

confluence_1 | 03-Apr-2020 21:40:02.110 WARNING [Catalina-utility-1] org.apache.catalina.valves.StuckThreadDetectionValve.notifyStuckThreadDetected Thread [http-nio-8090-exec-27] (id=[257]) has been active for [68,800] milliseconds (since [4/3/20 9:38 PM]) to serve the same request for [https://xxx-redacted-xxx/plugins/macrobrowser/browse-macros.action?detailed=false&macroMetadataClientCacheKey=1584284690678] and may be stuck (configured threshold for this StuckThreadDetectionValve is [60] seconds). There is/are [7] thread(s) in total that are monitored by this Valve and may be stuck.

Server setup

I'm using the official docker image atlassian/confluence-server running behind a Traefik proxy (SSL termination). Environment settings:

 - 'CATALINA_OPTS= -Xms256m -Xmx2g'
 - 'ATL_PROXY_NAME=my-redacted-domain.com'
 - 'ATL_PROXY_PORT=443'
 - 'ATL_TOMCAT_SCHEME=https'
 - 'ATL_TOMCAT_SECURE=true'
 - 'ATL_TOMCAT_MAXTHREADS=20'
 - 'ATL_JDBC_URL=jdbc:postgresql://xxxx:5432/my-db-user'
 - 'ATL_JDBC_USER=my-db-user'
 - 'ATL_JDBC_PASSWORD=xxx'
 - 'ATL_DB_TYPE=postgresql'
 - 'JVM_MAXIMUM_MEMORY=2048m'

 Confluence Version 7.3.2 (although this problem has stayed with me through several upgrades since initial installation last November).

[Patricia Dugan]

Hi G. If we may be of any help over at the Community Forum for Traefik, please join us there. Be well. -- Patricia, @traefik. http://community.containo.us/