(Data Streamer) Excel not connecting properly to com port

Hi
I have a problem connecting to a com port using data streamer. I know the problem lies with excel since there's basically no problem connecting to it elsewhere. When I try to connect to the com port I get an error message:

Unspecified error (Exception from HRESULT: 0x80004005 /E_FAIL))

When i dismiss it and try to connect again it says that the com port is busy, that it is already in use. I used Advanced Serial Monitor to check where the problem lies and there is no problem connecting with the com port at first. But when I try to connect with excel and get an error and after that I try to connect with the Advanced Serial Monitor instead it says that excel is using that com port. But I don't have a connection with it according to excel. If i close Excel and then try again to connect with the Advanced Serial Monitor it works since Excel isn't using it anymore.

The second time I try to connect to the com port with Excel i get the message:

Unable to connect to the device because it is already in use. Make sure it's not being used by another application the try again.

Does anyone know how to solve this problem?