error message: check your internet connection - first time trying to make a prezi

I would really love to try making a prezi, but when I click on "new prezi", I get an error message right away. It says to check my connection and that prezi support may help, but I have been reading the threads and none seem relevant.
I have made sure flash, java, cookies are enabled.
I have updated Safari and Flash.
I have tried to log in on another computer on the same wifi, and I get the same error message.
Please tell me what to do. I have never encountered error messages on any other sites on my macbook pro. It is usually so easy and intuitive - I have no idea where to start.