Explanation:

These messages appear in the Foxhound database engine console log when the Foxhound Monitor has given up waiting for a "connection failed" response to its attempt to connect to the target database:

Connection 1000002140 dropped by Foxhound because it failed to connect to target DSN RuralFinds_Bonnie after 16.1s (timeout threshold is 15.0s; see Foxhound Options) 
User "DBA" dropped event connection 1000002140 ("rroad_monitor_sample_loop")

Note that Foxhound does not give up trying to connect just because a connection failed, that's not what this kind of "timeout" is; for more information see Help - Foxhound Options - Connection Timeout.

To stop further attempts to restart start sampling for this target database after a timeout, click on Start Sampling, then Cancel Request.

To stop all further attempts to restart sampling after a time out, or to change how often the attempts are made, see Help - Foxhound Options - Timeout Retry.

It is also normal to see several messages like this when the Foxhound engine is forcibly stopped while it is sampling several target databases.

See also...
Help - Foxhound Options - Diagnostics
Help - Foxhound Options - Connection Timeout
Help - Foxhound Options - Timeout Retry