Error 100 No matches found for this user

This error is returned by Facebook itself. Unfortunately, the problem is that it can apply to many different situations, and it's difficult to understand the cause in a particular situation.

Generally, the following options may be considered:

1. The user deleted a chat with you
2. User is banned
3. The author of the dialog is not a regular user, but a public page

In the third case, you can reply to the user in Facebook itself by going to the social network from the service, but this reply does not work in real time due to the limitations of Facebook's API, so your reply may be uploaded to the service with a delay of up to 30 minutes.