I’ve factory reset this phone and installed latest Firmware. In RC there is option of T57w phone but not this t58w. Inexplicably, there seems to be no way to manually add this phone.
Is it possible that this phone simply won’t work. The office has T46S out the ying yang and they work fine.
try manual provisioning the phone
https://support.ringcentral.com/article-v2/assisted-provisioning-yealink-deskphones.html?brand=RC_US&product=RingCentral_MVP&language=en_US