We're having intermittent issues with 3CXPhone for Windows with a CTI phone attached, in a remote office with a Raspberry Pi SBC. The message we get is "3CX Phone for Windows could not establish a connection to the 3CX Phone System Web API. As a result, features like Contacts and presence information will not be available. You can still make and receive Phone Calls via SIP whilst we try and re-establish full functionality in the background." We've checked the antivirus and set up exceptions for 3cxphone, and recycled the 3CX Application Pool in IIS. Any suggestions?