That site's login process is, for all practical intents and purposes, inaccessible. I do not believe you're having any issue activating the link, per se, but with all else that comes after.
The login link itself triggers a java script which causes what looks like a standard login overlay window to appear. I did not try object navigation, but when doing the usual tabbing around I never even land in the edit box where you'd enter your login id, and all the other buttons and links as well as the X button to dismiss the window are unlabeled and just say, "blank."
This should be taken up with the site owner.
Brian - Windows 10, 64-Bit, Version 21H1, Build 19043
The ignorance of one voter in a democracy impairs the security of all.
~ John F. Kennedy