Trading bot - what is the maximum load an exchange server can take?
Finally, after 7 days of waiting, I got this answer from Bittrex:


  Your account has been re-enabled.
  "Your account was disabled for API-ABUSE.  Please refrain from making more than 1 request per second or you can expect your account will be disabled again"


Now you now it too, fellow bot-users: no more than 1 request per second !

HTH