non-Sixfab Connect SIM Cards

I have a number of IoT SIM cards procured through another vendor which use AT&T/T-Mobile/Vodafone networks. Is it possible to use those SIMs on the Sixfab Connect platform?

You cannot add and manage a SIM other than the Sixfab SIM on Sixfab Connect.

Thank for the confirmation. Sixfab connect appears to be a convenient platform to manage SIMs at scale. Other vendors offer an email system to provision and maintain SIMs which does not scale well.