Could not login xossipy site in laptop/smartphone why?

[~rp]

for login problem with any browser :
that browser cookies for this site might need deletion once.
each browser might have different method for clearing cookies.

generally suggested method :
visit following page in that browser

https://xossipy.com/misc.php?action=help&hid=3

above page consists of a link to delete browser cookies.
using that link, delete your browser cookies for this site.

close your browser. open it again & then try login process
if error message appears then please copy it & paste it here.