Hi Lola,
PTMSigDB is maintained by a separate group at the Broad and we really don't have any direct communication with them.
However, it does appear that they have a new link for their web service here:
https://proteogenomics.shinyapps.io/ptmsigdb/
Also, here is a link to their GitHub repository where you can reach out to them directly:
https://github.com/broadinstitute/ssGSEA2.0/should the first link cease working.
Hope this helps,
-Anthony
Anthony S. Castanza, PhD
Curator, Molecular Signatures Database
Mesirov Lab, Department of Medicine
University of California, San Diego