Failed to authenticate on INVITE to '<sip:XXXXXXX@XXXXXX'

The problem is that my asterisk requires a
Proxy Authentication because it receives an error 407.

I found on a website this meaning:
Failure to authenticate - 401 or 407?
If the origin server does not wish to accept the credentials sent with a request, it SHOULD return a 401 (Unauthorized) response. The response MUST include a WWW-Authenticate header field containing at least one (possibly new) challenge applicable to the requested resource. If a proxy does not accept the credentials sent with a request, it SHOULD return a 407 (Proxy Authentication Required). The response MUST include a Proxy-Authenticate header field containing a (possibly new) challenge applicable to the proxy for the requested resource.

Moreover appears that a
Proxy-Authorization: Digest username=“0123456789”, realm=“voip.eutelia.it”, algorithm=MD5, uri="sip:[email protected]"

Why in realm there is my other trunk ? eutelia? This one is vivavox.it