I am having this exact same error! I go to the store page, click on the link for ceremonial clothing and it asks me to login. I put in my credentials (I know they are right, they are stored in LastPass and I can login to the main church website) it acts like it’s logging in but then takes me back to the error page saying login. The same think happens if I try to add pants or shoes. I can select the sizes but it says to sign in to ship to me.
I’m attaching a screen recording. It isn’t asking for my credentials because it asked the first time. I have tried clearing cookies and logging in again. I have tried on my iPhone, iPad and desktop over WiFi and on cellular. Don’t know what else to try.
Apparently the forum won’t let me attach video so I am attaching 3 screenshots showing before during and after.