BESFillDB discarding client messages

I have two clients reporting into the BigFix server. However, these do not appear in the console. They do post their reports successfully. However, the FillDB.log on the server is showing the following:

Discarding message with sequence range (x, x) from computer x because we have no existing sequence number.

Does anyone know what this might mean? I haven’t been able to find any posts relating to this message - specifically where “no existing sequence number” is mentioned.

Are they installed recently?
Have you tried to reset the BES Clients?

I 2nd the suggestion to try resetting the Clients. For reference, please see https://developer.ibm.com/answers/questions/294187/how-do-i-reset-a-bigfix-client.html