Defender for Endpoint Conflicting with Internal Firewall Authentication

Hi Security Experts,

After onboarding a few devices into Defender for Endpoint, I noticed that those machines started having connection drops to the company’s internal firewall.
They constantly re-authenticate before regaining web access.

Devices not onboarded into Defender don’t experience this issue.

Could Defender’s network protection or proxy policies be interfering with the internal firewall authentication flow?
Any recommendations on how to keep Defender active while keeping the internal firewall as the primary control point?

Thanks for any suggestions,
Luca