IN APIM I am facing this issue.I tried multiple time but still it shows not found.
I already created logicapp with my name and trying to configure it from APIM . Checking it in API's logicapp resource.
The error generally occurs when your logic App don't have appropriate access to configure and your APIM regions are different from logic App.
Issue reproduced from my end getting same error when my logic App and APIM are in different locations.
Refer this MS document import a logic App which supports multi-tenant Logic Apps environment.