OSX 10.15 debug AUv3 in Logic


I am trying to debug an AUv3 in Logic 10.5 in OSX Catalina.
But when I build my plugin in Xcode, I get the following error message:

"Embedded binary is not signed with the same certificate as the parent app. Verify the embedded binary target’s code sign settings match the parent app’s."

AUv2 works fine. So this must be something specific to AUv3.
Any ideas, what I need to do, to make the AUv3 build?
For example: how can I find out, what certificate Logic was signed with? And can I even get that certificate?

Note: I am on JUCE 5.4.7.