Re: Endorsement Application submission error after passing exam
If it's been days since receiving the email telling you to go through the endorsement process and you're still seeing this error, it's very likely to do with the email address you registered with Pearson VUE being different to the one you're trying to use on the ISC2 member portal.
I have no idea why people think these wouldn't need to match?
Regardless of the cause, you'll need member support to resolve your issue. Keep calling them until they answer as emailing or leaving a voicemail takes weeks to get a response. Alternatively, try calling out their tardiness on Twitter.