Hey Felicia! Do you get the 500 error immediately after clicking the invite from the email?
It would be great to see the process on a call. Here is my calendly link to book a quick call and troubleshoot: https://calendly.com/soniapiorek/15min

Hi Sonia, 

Just booked for today. When I click accept from the email, it says sign in or sign up, and when I sign in it goes to the 500 error message.

Thanks for your help, appreciate it.

Before we speak later today, when it asks you to sign in, are you using the email and password you used before to set up your Decile Hub account?

Yes that's correct.

Hey Felicia, I am glad we could resolve the problem. I have also removed the account you set up so that you can focus on the account with your Partner, as we discussed.