Cannot start sample app AnalogWatch on emulator - certificate error

I want to get started in Web Applications for Smart TV.
I managed to set up Tizen Studio. I already have a emulator window running, showing the color bars and “ATV”. I loaded the sample project “AnalogWatch”.
If I do “Run As / Tizen Web Simulator Application (Samsung TV)” I can see the app and the clock
If I do “Run As / Tizen Web Application” I get “Installing the package… > Fail” and in Console window I find

Launching the Tizen application…
# If you want to see the detailed information,
# please set the logging level to DEBUG in Preferences and check the log file in ‘F:\tizen\data\ide\logs/ide-20220402_202906.log’.

[Initializing the launch environment…]
RDS: Off
Target information: T-samsung-6.5-x86
Application information: Id(aKX0hVCTcq.AnalogWatch), Package Name(aKX0hVCTcq), Project Name(AnalogWatch)
[Transferring the package…]
Transferred the package: wgt stream → /home/owner/share/tmp/sdk_tools/tmp/AnalogWatch.wgt
[Installing the package…]

install aKX0hVCTcq.AnalogWatch
package_path /home/owner/share/tmp/sdk_tools/tmp/AnalogWatch.wgt
app_id[aKX0hVCTcq.AnalogWatch] install start
app_id[aKX0hVCTcq.AnalogWatch] installing[10]
app_id[aKX0hVCTcq.AnalogWatch] installing[13]
app_id[aKX0hVCTcq.AnalogWatch] installing[15]
app_id[aKX0hVCTcq.AnalogWatch] installing[18]
app_id[aKX0hVCTcq.AnalogWatch] installing[21]
app_id[aKX0hVCTcq.AnalogWatch] installing[23]
app_id[aKX0hVCTcq.AnalogWatch] install failed[118, -12], reason: Check certificate error : :Invalid format of certificate in signature.:<-2>
spend time for wascmd is [232]ms
An exception occurred
(Installing the package… > Fail)
An exception occurred
Unexpected stop progress…
(1.723 sec)

I am completely lost here. In some places I read that for emulation no certificates are needed. But whatever, I indeed have a certificate.