It could be that your router is struggling with the amount of connections Tor generates. Consumer class routers are known to have a relatively low number of max. connections or connections per second.
>> You have total transfer per day limited, but do you have total >> transfer per second limited using BandwidthRate and BandwidthBurst? > > From my /etc/tor/torrc > > BandwidthRate 75 KB > AccountingStart day 12:00 > AccountingMax 1 GB > > -- > To the agents of the N.S.A. reading this email: "The right of the people > to be secure in their persons, houses, papers, and effects, against > unreasonable searches and seizures, shall not be violated, and no Warrants > shall issue, but upon probable cause, supported by Oath or affirmation, > and particularly describing the place to be searched, and the persons or > things to be seized." 4th Amendment to the United States Constitution. >