Did Not Answer in Messenger Means?

Did not answer = Either did not go through, or rang and the recipient didn't answer/decline.

How do I know if someone has ignored me on Messenger?

To do so, message the person from your account and at the same time, ask someone else to message that person. Keep a check on the delivery icon for both accounts. If the other person's delivery icon changes from Sent to Delivered and yours is still showing Sent, it means they have Ignored you.

How do you know if someone is ignoring your calls?

The Number of Rings

If upon placing the phone call, it rings only once or twice and goes to voicemail then your calls are probably being declined. This is because the recipient of the phone call has manually clicked the “decline” call option on their phone.