According to the Messenger Support Center, if someone who you’re not connected with on Facebook sends you a message, you’ll receive a connection request. Read: Can I follow someone on Facebook again that I’ve Unfollowed?
However, if you ignore a connection request, you won’t be able to see the message again. If you want to talk to the person who sent a request you ignored, you can send them a message. Your message will go to their connection requests. See: My Blocked List on Messenger – How to Unblock People on Facebook Messenger
How to See Connection Requests on Facebook Messenger
To see your connection requests on Messenger, do this;
iPhone:
1. From Home, tap People.
2. Tap Message Requests at the top.
Android:
1. From Home, tap People.
2. Tap People.
3. Tap Message Requests.
From here, tap the connection request and choose:
– Accept to open the conversation
– Ignore to remove the request