Hi @jumbo.zimmy,
Thanks for your message and a warm welcome to the Cubasis forum!
First of all, please note that Apple introduced Audio Unit on iOS many years ago, which can be seen as their successor of Inter-App Audio, and provides much more flexible options. Check out how easy it is to load and use Audio Units with Cubasis in our Getting started with Cubasis tutorial.
Inter App Audio comes with many limitations, which we’ve described in our dedicated Limitations of Inter-App Audio article.
I suggest to launch the Stand Alone app versions of your IAA plug-ins in use first, which might help to see them properly loading in Cubasis afterwards.
In addition, please check out if there are AU versions of your IAA plug-ins available, or let the app vendors know, that you want to see them updating their plug-ins (to make them aware about the demand).
Please let me know if this helps to resolve your problem.
Best,
Lars