Dear Justin:
I could not find new files here: MacKerell Lab
Is it the right place? There, what I see is still as below, even after a browser refresh.
CHARMM36 Files for GROMACS
CHARMM36 force field in GROMACS format, including CGenFF version 4.6 and the CHARMM36m protein force field revision. Updated July 2022.
The current version of the CHARMM36 port for GROMACS is dated July 2022, corresponding to the CHARMM toppar release of the same date. It contains the same topologies and parameters as the July 2021 update (including the option to use LJ-PME with lipids, given in the second port listed below) and adds some new parameters, and modified amino acids, among other items. See the “toppar_history” file in the CHARMM toppar distribution above for details. Files updated 12/8/2022 to fix typos related to TIP4P-Ew water parameters and an issue related to cholesterol NBFIXes.
I don’t have a very good solution for this aside from leaving a bunch of previous ports online that have bugs on them. In my experience, users do not read provided information very well so I am leery of doing this, knowingly allowing someone to download something that is broken. We have done this in the past (and you see in the list on Alex’s site) when we have found more serious issues but those were cases in which things were online for a long time before an issue was discovered. In the latest port, issues have been detected within a few days. I have been posting updates on the third-party tools section of the forum (where I post all C36-related announcements) so I hope this is enough notification. Aside from the cholesterol issue, most things that have come up have been rather obvious errors in mostly non-standard features.
Your question does not have anything to do with the topic of this post. But anyhow … The link you posted works for me. I would suspect something blocking your connection. Start with contacting your internet provider. Can you access http://mackerell.umaryland.edu/ at all?
Then I would think that either your internet service provider (university?) is blocking traffic to that site or the University of Maryland is blocking access from your IP. Perhaps there has been too much bot traffic, or something.