[fcgid:warn] mod_fcgid: process xxx graceful kill fail, sending SIGKILL

When I try to import a big file in Phpmyadmin it aborts after some time with a 500 error. The maximum size I can import is about 33MB. The error log shows the above mentioned error: [fcgid:warn] mod_fcgid: process xxx graceful kill fail, sending SIGKILL

I did some search on the internet but the only thing relevant that I could find was changing the timeout in a fcgid.conf file. That was an old post and on the mentioned location there was no longer such a file. But I changed it in the only location where I could find such a file: /etc/apache2/mods-available/cgid.conf However, that had no effect. So: my question is: what should I do?

This is a new Virtualmin installation - just a few days old - on Ubuntu 18.04.