login bug with coockie by google

i open gmail
i login
i open zoho
i login by google account
no problem

i go to gmail
i open a zoho mail (response to forum post)
i click the link to zoho forum in mail
it say you must login to response

but i am allready loged in in google and zoho

so now i have to login again to the forum
then i have to search the post
and then i can read it and response

then i can go to gmail
click again on the zoho forum link
then i have to login to zoho forim again

all the time

that should be fixed

why login to zoho if i am allready loged in?

thanks