There is a problem with the link above, we are looking at it now.
Mean while, try this
I just tested the Discord invitation and it is still working:

Thank you, but for discord I can't join the channel because the member of channel is 100 person.

Posted using Partiko Android

Are you sure it's not because you have joined 100 servers already? Discord does not allow one user to be in more than 100 servers. We currently have only 91 members in total.

oh... I will check it

Oh... you are right, I have joined the channel.. thank you!