FTP download pool error

I'm using my Service Module to FTP down a small text file from my website. On my tablet which has only wifi, if I turn off or otherwise lose my wifi connection, after a few minutes I get this error in the log:

java.util.concurrent.RejectedExecutionException: pool=20/20, queue=0/0

My Service Module is trying every 30 secs to download the file. I'm detecting a wifi connection using the ToggleLibrary. Should I be stopping the FTP attempts when I know the wifi is down?

Thanks...