Error reported when trying to send an email report (no replies)

The nightly cron reports strange permission error when trying to send an email report:

Error in the last Piwik archive.php run: 
1 total errors during this script execution, please investigate and try and fix these errors. First error was: Got invalid response from API request: [XXX.de]. Response was 'task,output
CoreAdminHome.purgeOutdatedArchives,Time elapsed: 0.839s
API.sendReport_2,"ERROR: Sie können auf die Ressource nicht zugreifen, da Sie dafür mindestens 'view' Rechte benötigen."
PrivacyManager.deleteReportData,Time elapsed: 0.018s
PrivacyManager.deleteLogData,Time elapsed: 0.001s
Piwik\Plugins\CorePluginsAdmin\MarketplaceApiClient.clearAllCacheEntries,Time elapsed: 0.045s
CoreAdminHome.optimizeArchiveTable,Time elapsed: 0.498s
DBStats.cacheDataByArchiveNameReports,Time elapsed: 33.870s'

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This seems to happen for just one piwik instance here and I don't understand it as archiving otherwise works and it should use the superuser, isn't it?


Regards,

Thomas