Hi. I'm wondering whether anyone is having trouble logging into the mona-tore crypto exchange?

https://monatr.jp/

I logged in successfully the first time using my Yahoo Open ID and sent some funds there to buy Mona. Since then I've not been able to log in at all using the same method.

One part of the screen says:
Logged in successfully.
Duplicate entry 'https://me.yahoo.com/a/xxxxxxxxxxxxxxxxxxxxxxxxxx' for key 'xxxxxxx'
(the xxx's blank out assigned characters that might be specific to me)

The top part of the screen says:
User ID(x)Not logged in                   [ Login or Register ]


So one part of the page says that I'm logged in, the other part says I'm not. Has anyone encountered this problem before?  And has anyone any ideas of how I can successfully log in to access my funds?