Switching to myself (Multisite subdomain only)

Hi-

I am using User Switching successfully on my multisite with all subsites with a mapped domain. But it doesn’t work on the subsites with a subdomain. The switcher tells me I just switched to “Lin” (that’s me) – and suggest I switch back to “Lin”. Of course, clicking switch back doesn’t work and I have to login anew.

I read another post where you said that the COOKIE-DOMAIN statement in wp-config creates that problem. I have that statement too – because I cannot login at all without it (Cookie Error). So what do you suggest? How can I use User Switching for the subdomain subsites?

Thank you,

Lin