You mean 3.0.19.4? or just really 3.0.19? I think I have all the files with me... In total it's like 5gb of files just to store every version TeamSpeak 3 compatible with the server.
I looked up and the link on archive still works: 3.0.19
One of the reasons that I'm using archive is also because it's the official way to get these files, if I host in the near future someone could say these are the modified files without actual proof, but for archiving purposes I also have the mirror of every client version (not servers tho)
Yes the page opens, but try to download the 3.0.19.4 x86 file, it goes to error 503, i waited 20 minutes refreshed the page and waited more it never started the download