Only the background map for the map service 'Bing Maps (aerophoto)' is not shown anymore, other map services are still working.
Its license in
Help -> License -> Bing Maps (valid until ...)
is listed as expired and thus disabled.

https://www.ptvgroup.com/en/solutions/products/ptv-vissim/knowledge-base/faq/visfaq/show/VIS19070/