Supermodule update fails becaus of 'Permission denied (publickey)'

Supermodule Update

Gerrit Instance: qt-projectProject: qt/tqtc-qt5
Branch: tqtc/5.13
 
Running update...
 
Fetching branch tqtc/5.13 of ssh://codereview.qt-project.org:29418/qt/tqtc-qt5
Retrieving 5.13 branch head of qtopcua for updates
Retrieving 5.13 branch head of qtknx for updates
Retrieving 5.13 branch head of qtmqtt for updates
Retrieving 5.13 branch head of qtcoap for updates
New submodule update commit: 0a875e93407c1af59fa36ee833b4a025056823b5
Error pushing submodule update commit: Error running git --git-dir=/home/vmbuilder/ci-working-dir/git-repos/qt-project/qt/tqtc-qt5 push ssh://qt_submodule_update_bot@codereview.qt-project.org:29418/qt/tqtc-qt5 0a875e93407c1af59fa36ee833b4a025056823b5:refs/for/tqtc/5.13: exit status 128
Stdout:
Stderr: qt_submodule_update_bot@codereview.qt-project.org: Permission denied (publickey).
fatal: Could not read from remote repository.
 
Please make sure you have the correct access rights
and the repository exists.