JCMA Failed to Load? 7 Causes and Fixes

A line in atlassian-jira.log saying the Jira Cloud Migration Assistant failed to load looks like the end of your migration, and it is almost always one dependency, one cache directory, or one blocked domain.

If the Jira Cloud Migration Assistant failed to load error is what brought you here, the first job is telling two different failures apart, the plugin refusing to start on Data Center, and the migration screen that will not render in a browser. The causes below are numbered in the order you should check them.

First, Tell the Two Failures Apart

Open Manage apps and look for the Jira Cloud Migration Assistant entry. A failed to load or unable to start the plugin container state puts you in section one, a server side startup problem. An enabled plugin with a blank Migrate to Cloud screen puts you in section two, a rendering or connectivity problem.

The fixes do not overlap: clearing a browser cache will not fix a missing bean, and restarting Jira will not fix a blocked domain.

Jira Cloud Migration Assistant Failed to Load at Startup: 4 Causes

1. Jira Software or Jira Service Management is missing or mismatched

The JCMA plugin has hard dependencies on Agile components. On a Jira instance where Jira Software is not installed, or where an older Jira Service Management build still sits in the installed plugins directory, the plugin throws an unsatisfied dependency error naming a bean such as RapidViewService or jsdExportService, and it never starts.

Fix: check Administration, then Applications, then Versions and licenses, and confirm Jira Software and Jira Service Management are present at versions compatible with your Jira core version. Upgrade the mismatched product, remove outdated app jars from installed_plugins, then restart Jira, a rolling restart is enough on Data Center. On deployments that intentionally run Jira Service Management only, a community reported workaround from the Jira issue tracker is to install Jira Software on the same deployment, no trial license required, and restart.

2. Stale plugin cache or a disabled row in pluginstate

Jira caches bundled and OSGi plugins under JIRA_HOME. When a plugin upgrade leaves that cache behind the database state, the plugin fails to load on startup even though the jar is current.

Fix: stop Jira, back up the database, delete the two hidden cache directories JIRA_HOME/plugins/.bundled-plugins and JIRA_HOME/plugins/.osgi-plugins, then start Jira again and let them rebuild. If it still fails, check the pluginstate table for entries that should be enabled but are not, and look for legacy or disabled plugins that are known to interfere, the Watcher Field plugin comes up repeatedly in Atlassian's plugin container article.

3. The JCMA build does not match your Jira version

Older JCMA versions are no longer supported, and a plugin built for a different Jira major version can fail bean creation on startup or refuse to enable.

Fix: go to Manage apps, remove the current Jira Cloud Migration Assistant build, and upload the latest version from the Atlassian Marketplace, or take the version bundled with your Jira release. Re-check the failed plugin report in the log after the restart, the entry should be gone. Run the newest JCMA available for your instance before every migration, Atlassian ships fixes for these load failures in point releases.

4. An Advanced Roadmaps or preflight check blows up on startup

A less common variant shows a bean creation failure inside a preflight check, the log names something like advancedRoadmapsOutdatedCheck and the plugin report marks the migration plugin as failed. The underlying data, an outdated Advanced Roadmaps version or a missing Agile app, is the real cause.

Fix: confirm the Advanced Roadmaps app is installed and current for your Jira version, confirm Jira Software is enabled, clear the plugin cache as in cause 2, and restart. If the report still fails, send the log excerpt to Atlassian Support with your Jira and JCMA versions, this class of failure is version specific.

JCMA Failed to Load in the Browser: 3 Causes

5. Firewall or proxy is blocking the migration domains

The migration screen pulls UI components from Atlassian hosted domains, including mp-module-federation.prod-east.frontend.public.atl-paas.net for the Migration Assistant interface, and it talks to the migration service over HTTPS. If your firewall, proxy or egress rules block those, you get a blank screen or a failure at Connect to Cloud while the plugin itself is healthy.

Fix: have your network team allow the top level domains with subdomain depth, *.atl-paas.net, *.atlassian.com, *.atlassian.net, plus the migration service URLs in Atlassian's IP addresses and domains article. If Jira uses an outbound proxy, set the JVM arguments from Atlassian's outbound proxy article in setenv.sh. Then check atlassian-jira.log for connection errors to those URLs, a clean log on retry means the network path is open.

6. Browser cache, extensions, or an unsupported browser

Stale cookies and cached resources from an old Jira session break the migration screen on an otherwise healthy instance, and ad blockers or privacy extensions frequently block the module federation requests it depends on. Internet Explorer has never rendered this screen, Atlassian's own article tracks the blank page IE11 produces, and only current Chrome, Edge, Firefox and Safari builds are supported.

Fix: retry in a private or incognito window first, the test Atlassian's troubleshooting guide recommends. If the screen loads there, clear site cache and cookies for the Data Center URL, disable extensions for the session, and use a supported browser. Still blank? Move to cause 7.

7. JVM file encoding is not UTF-8

After a JCMA update, some instances serve the migration screen's JavaScript with encoding errors, the browser shows an empty page and the log records a malformed JSON or source map exception on a fe-resources resource. The cause is JVM file encoding on the host, not your data.

Fix: edit bin/setenv.sh, find JVM_SUPPORT_RECOMMENDED_ARGS and set it to include -Dfile.encoding=UTF-8 and -Dsun.jnu.encoding=UTF-8, then restart Jira. The screen should load on the next attempt.

Also Check Permissions and Cloud Site Reachability

Two situational causes look like load failures but are access problems. You need Jira system administrator permission on the source to open Migrate to Cloud, and the account connecting to Cloud must be able to see the destination site. If the plan reports that it cannot check for projects in your Cloud site, the sandbox has been deleted or the site subscription is inactive, both visible from admin.atlassian.com under Apps and Billing.

A Triage Order That Takes 30 Minutes

1. Open Manage apps, confirm the plugin state and note the exact error text.
2. Confirm Jira Software, Jira Service Management and Advanced Roadmaps versions against your Jira core version.
3. Stop Jira, clear the two plugin cache directories, restart, recheck.
4. Update the JCMA build if it is behind your Jira version.
5. Test the screen in an incognito window on a supported browser.
6. Check atlassian-jira.log for blocked domains, then get the allowlist fixed.
7. Set UTF-8 JVM encoding if the screen is blank after an update.

Only after all seven pass should you suspect the migration plan itself.

Resources

• JCMA Post-Migration Checklist: What to Clean Up After Migrating
• What Is JCMA? Why It Creates Duplicate Fields
• Atlassian: Troubleshoot migration with Jira Cloud Migration Assistant
• Atlassian: IP addresses and domains for Atlassian cloud products
• Atlassian KB: Unable to start the plugin container for Jira Cloud Migration Assistant plugin

Once the tool loads and your first test plan runs, keep an eye on the field list it creates, a re-run on an already migrated project is how "(migrated)" duplicates multiply. Migration Field Cleanup for Jira finds those suffix fields, pairs them with the original, shows the issue count for each pair, and merges with one click, copying values only into an empty original, so existing Cloud data is untouched. It runs on Forge inside your own instance, and teams of 50 or fewer users can use scan and merge free. Get Migration Field Cleanup for Jira.