Hi @tao.su

In order for a recommendation to take place, we'll typically require more information.

Specifically,

1. What version of EMA C++ are they using?
2. Is this a new application or an existing one that has been running for a while?
3. If they are starting to build it, has the client gone through the recommended learning material?
4. Exceptions can occur for multiple reasons and without any context of what the code is attempting to do, i.e. no specific code examples, it will be difficult to help. What we can do is provide a coding example of an action they are trying to do - this usually helps. But will need to specifically know what they are doing.
5. They can also review section 8.3 within the C++ Developer Guide which discusses Exceptions. For example, that specific exception indicates an invalid usage of an interface - they may be passing in incorrect parameters into whatever interface they are using. This may help them understand why this is occurring.

Thanks.