AQtime fails to load host application (sort of)

I want to profile a Delphi DLL using the performance profiler. So I load that DLL and I also give the host application and the working directory.

Then I start it. AQtime is busy for a few seconds and then nothing happens. If I look at the process list, I notice that the host application has been started, but it never starts up completely, it actually stays always invisble although it is a windowed application.

The last entries in AQtime event view are:
Event    Thread ID    Time
Module loaded: C:\Program Files (x86)\SmartBear\AQtime 8\x64\Bin\aqProf.dll;  Base address: 0x0000000015B80000  File Size: 1211344 Version: 8.70.2686.647    27324    14:52:16:901
Module unloaded: C:\PROGRAM FILES (X86)\SMARTBEAR\AQTIME 8\X64\BIN\AQPROF.DLL;  Base address: 0x0000000015B80000    27324    14:52:16:910
Module loaded: C:\Program Files (x86)\SmartBear\AQtime 8\x64\Bin\aqProf.dll;  Base address: 0x0000000015B80000  File Size: 1211344 Version: 8.70.2686.647    27324    14:52:16:912
Module loaded: C:\Program Files (x86)\SmartBear\AQtime 8\x64\Bin\aqComm.dll;  Base address: 0x00000000159B0000  File Size: 336336 Version: 8.70.2686.647    27324    14:52:16:945
Module unloaded: C:\PROGRAM FILES (X86)\SMARTBEAR\AQTIME 8\X64\BIN\AQCOMM.DLL;  Base address: 0x00000000159B0000    27324    14:52:16:954
Module loaded: C:\Program Files (x86)\SmartBear\AQtime 8\x64\Bin\aqComm.dll;  Base address: 0x00000000159B0000  File Size: 336336 Version: 8.70.2686.647    27324    14:52:16:955

I tried our 32bit and our 64bit version, it's the same. I also tried it when integrated in Delphi or the standalone AQtime application: it does not work

System:
Windows 10, Business, 64bit: Microsoft Windows [Version 10.0.16299.309]
Delphi 10.2 (Tokyo), Update 2
AQtimePro version 8.70.2686.7

What can I do to make it work?

Best regards and TIA - StarFire