Trouble getting document with documentclass{aa} to compile

I am having trouble running this Example of a manuscript header with structured abstract which the journal of Astronomy and Astrophysics provides on their webpage. I have downloaded the "A&A LaTeX macro package" which they provide on their website, and put all files into the document folder.

When I copy-paste the above example into a tex-file, and try to typeset, I first get an error that there would be too many }. After deleting the one which looks too much I get the error/message:

IMPORTANT

Class aa Warning: The running head built automatically from author and titlee xceeds the pagewidth, please supply a shorter form with authorrunning and/or titlerunning prior to maketitle on input line 48.

IMPORTANT

(usr/local/texlive/2019/texmf-dist/tex/latex/txfonts/t1txtt.fd))
*

I am not sure what that means, and I did not find anything relevant when googling for that error message. Any suggestions?