Hotmail cannot receive verification emails from one sender

Hello,

I recently created a new Hotmail account. I can receive emails from other senders without any problems, and my inbox is not full.

However, I cannot receive verification emails from Splitscreen Studios, the company behind the game Dino Storm.

Their support team told me that Microsoft reported my inbox as unavailable for receiving emails.

I have checked my junk email folder and blocked senders list, and I added Dino Storm's emails to my safe senders list.

Could someone help me understand why these emails are not being delivered and how I can fix this issue?

Thank you!