Welcome to the community, SunriseIsNotTrustWorthy
Since we are a customer-helping-customer forum here, we cannot change the system settings. But from what I understand, the address megacorpone.com is a known IT test site with malware samples? Sunrise Surf Protect is doing a great job here and blocks the access automatically.
The message from Firefox in the second image is only triggered by the redirect to the Sunrise warning page. The browser suspects a manipulation behind the sudden certificate change and rings the alarm.
There is no error and the security feature works exactly as it should. If this blocks your OffSec work, you can simply disable “Surf Protect” yourself in your My Sunrise portal under your subscription settings. Please note: If Surf Protect is currently included in your plan as a free promotion, I am not sure if you can reactivate it for free later on.
Cheerio cosmo