It seems like the error you're encountering is due to the SIP URI you're trying to use already existing in the system. The Plivo platform indicates that this URI has been used by another user, which is why you're seeing those errors.
One way you could resolve this is to try using a different, unique URI. It might help to try a format like \[organization name\].sip.vapi.ai;transport=udp or similar to ensure uniqueness. Check with your team to see if there might be any other existing setups using the same URI.
If you're having trouble locating any previously created UIDs or configuration details, I'd recommend reaching out to Plivo’s support to see if they can provide more detailed logs or help track any existing setups that might be causing a conflict.