Originally Posted by
EDIflyer
Hmm, from the posts above I thought I had it sussed - login using old SPG number/pwd on SPG site (as email was giving Marriott account). However no such luck - SPG number/pwd just gives a login error. I know password is correct as it's stored in my password manager and worked last week!
Will just leave it for a few days and see if it sorts itself out.
Try private browsing / Incognito. I have the same issue but private browsing allowing me to log in SPG with existing credentials.