error in mailing list subscription link

The mailing list subscription links posted in http://lammps.sandia.gov/mail.html seem to be down. The error message is below:## Bug in Mailman version 2.1.9

We’re sorry, we hit a bug!

Please inform the webmaster for this site of this problem. Printing of traceback and other system information has been explicitly inhibited, but the webmaster can find this information in the Mailman error logs.

sourceforge had a major hardware failure and have been restoring their
services from backups over time. mailing lists were (understandably
the last to re-activate). please try again.

axel.