My @gdoc/@gtable stopped working

If you had a working @gdoc or @gtable that used to work and 'suddenly stops' but you still see it in preview mode the problem is probably (about 99.9% confidence) with your web host.

Both of these pluskit additions depend on reaching google docs and it's sadly not uncommon for web hosts to reconfigure the servers in a way that breaks them.

Your only optinon is to contact your web host and ask them what they changed