Can't install VirtualBox Guest Additions.

Hello, I have problem installing VirtualBox Guest Additions. My host is 5.0.7-200.fc29.x86_64 And when I run the VGA installer on the guest system I get: [erik@localhost VBox_GAs_6.0.4]$ sudo ./VBoxLinuxAdditions.run Verifying archive integrity... All good. Uncompressing VirtualBox 6.0.4 Guest Additions for Linux........ VirtualBox Guest Additions installer Removing installed version 6.0.4 of VirtualBox Guest Additions... Copying additional installer modules ... Installing additional modules ... VirtualBox Guest Additions: Building the VirtualBox Guest Additions kernel modules. This may take a while. VirtualBox Guest Additions: To build modules for other installed kernels, run VirtualBox Guest Additions: /sbin/rcvboxadd quicksetup <version> VirtualBox Guest Additions: Building the modules for kernel 5.0.7-200.fc29.x86_64. VirtualBox Guest Additions: Look at /var/log/vboxadd-setup.log to find out what went wrong VirtualBox Guest Additions: Running kernel modules will not be replaced until the system is restarted VirtualBox Guest Additions: Starting. VirtualBox Guest Additions: modprobe vboxsf failed [erik@localhost VBox_GAs_6.0.4]$ Perhaps someone on this list has overcome this problem and would explain what I did wrong? The /var/log/vboxadd-setup.log was of no help. -- Thanks, Erik P. Olsen