Suit CRM Help with 404.

When I'm trying to connect Horizone integrator (when we have a call from someone in the CRM contacts, the integrator show the CRM contact name, open the CRM contact and register the phone call) with Suitecrm, the integrator cannot accept credentials for Suitecrm. The message from Horizon integrator is- The remote server returned error (404) Not found.
The integrator worked fine till April 2021

Many more task to do .but must be 1 by 1. just looking for long association with skilled Developer.

Cheers!
Sandy