I should have plenty of bandwidth and the connection passed a VoIP quality test. Both locations have the ISP and service level.
Both locations also have the same router (Netgear AC3200). Previously, both locations had Asus NT66U routers, I replaced both with the Netgear routers while troubleshooting. The remote location phones run through an unmanaged switch. At the primary location where the PBX server is, everything is hooked directly into the router.
I’m starting to think it’s an issue with my PSTN connection since internal calls between offices are fine. I’ve created a support ticket with my trunk provider (1-Voip) to see if they can help me fix the issue.