Links starting with www.math.uga.edu seem to be broken. They can be corrected by removing the www part. For example math.uga.edu/~shifrin/ShifrinDiffGeo.pdf and math.uga.edu/~shifrin/ShifrinDiffGeo.pdf or math.uga.edu/~pete/2400full.pdf and math.uga.edu/~pete/2400full.pdf

There are many posts with such links.

In facts, this is mentioned in Pete L. Clark's profile. Quote:

I considered whether I should first ask somebody related to uga.edu whether there is some hope that the longer links might work again. (In which case I would unnecessarily bump a lot of questions.)

But since now I have discovered that this problem is already from 2015, there is probably no much hope of that.

I am not sure whether something can be done about comments containing such links. I tried to find some of them. However, this query returns a lot of false positives. (Since Text LIKE '%uga%' matches things like conjugate.)

@MartinSleziak What about looking for www.math.uga?

@DanielFischer Have you edited some of them? When I tried a few, I found link starting without www.

@MartinSleziak Yup, edited most, deleted a small number of obsolete ones.

Wow! Thanks for that.

I'd say that the amount of work that moderators do is underrated.

[ SmokeDetector | MS ] Few unique characters in answer, no whitespace in answer, repeating characters in answer: Arrange 10 points on five lines where each line(intersecting) has exactly 4 points by priyam on math.stackexchange.com