Cannot fetch emails from mail list anymore

Hello everyone,
I have subscribed to Lammps mail list maybe two or three years ago with this email address, and I successfully received the posts from the mail list until several months ago.
However, I found that recently there is no new emails from the mail list appeared anymore in my email box. I have tried to re-subscribe to the mail list, however, an error poppoed up. Please see the attached figure. I am sorry that I did not find any instructions on the subscribing page or on
Could you please give me some guides to fix this problem?
Any help would be much appreciated!