How to change LinkedIn credentials for live streaming (webcast) + Failed to initiate live streaming

Hi,

I am testing the live streaming of a webcast with Linkedin and I am facing the following two difficulties:

1) I would like to change the Linkedin credentials for live streaming of the webcast. Once I have entered some credentials, I seems that I cannot change/remove them. I can only change the title of the post. 

2) I have succeeded showing the webcast in my Linkedin account, seemed to be easy. But now, doing some more tests and following the same steps, I am getting the message "failed to initiate live stream". Any idea of the reason?

Thanks in advance for your help.

Eneris