Hello @Antony.ccna ,
Welcome to the Poly Community.
The Poly GroupSeries is not natively compatible with Microsoft Teams. If you have registered this to Office 365 some restrictions may apply.
Poly offers a currently free service called RealConnect for Teams which is free until the End of June and after this with competitive pricing.
I suggest you work with a Poly reseller on the best solution for you.
Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.
I can second what Steffen is saying. The Group Series is a "Standards Based" video end point that does not currently run Teams Natively and may not ever. However it absolutely can participate in Teams meetings via an Interop License. One such license is Polycom's Real Connect which is free till June. I've been using Real Connect since last year and been successful with it.
If you want to learn more about Real Connect, these blog posts are extremely helpful - even if they are a little dated. I knew nothing about this stuff a couple of years ago - so it can be done!