Hello @MarcieM193 ,
Here's information on suspended bounces, and why contacts will end up in suspension.
If you believe a valid email address is bouncing as non-existent erroneously, it'd likely be worth reaching out to that contact or their email provider, to see if they have any insight why they're responding to our servers claiming its non-existent. You're also welcome to contact Deliverability to see if they have any specialized insight they can offer regarding a particular contact, or to see if any logs can be pulled.