Yii2: Not Found (#404): Unable to find debug data tagged with '5578effb0790c4.13707485'

I removed files from frontend/runtime/debug and frontend/runtime/cache and nothing was changed.

But when I removed all folders from frontend/runtime then it started to work.

One reason could be missing write permissions for the runtime folder. The Debug Tool Bar creates there another directory debug which is used for *.data files.

This happens easily if the web server has its own user which differs to the user that has created the runtime folder.

I tried the info above without luck (and I suggest people here do the same, as in most circumstances it will solve your problem). But what worked for me was running. tail -f frontend/runtime/logs/app.log and it told me that there was an error with a table that it expected to exist but did not. Once I fixed that underlying issue my problem went away. In my specific case, I had the following enabled but no corresponding table/s.

'authManager' => [
    'class' => 'yii\rbac\DbManager',
],

Once I commented/removed it from my config, everything started working.