Before you get too deep into troubleshooting techniques, it is a good practice to consider the following questions:
Were there physical changes to your network that occurred recently?
If another device is placed in the Sensor's position, does that device receive traffic?
If the Sensor is in L2 mode, are your network's services still affected?
Are you using approved Trellix SFP, SFP+, QSFP+, or QSFP28 with your Sensor? (For a list of approved hardware, see Trellix KnowledgeBase article KB56364.