turns out AdWords limits to 25 campaigns per account..

Just hit an Adwords limit of 25 campaigns per account. Surprisingly, Google Adwords Editor complained with unfriendly message "error code 17, remove something from your account" when I tried to create new campaing in it. I had to go to adwords account online and try adding new campaing there, only after that I got a clear explanation that the limit is 25 campaigns per account.