Unrecognized configuration section <startup>
Getting this error when executing ./build: MSBUILD : Configuration error MSB4136: Error reading the toolset information from the configuration file "System.Configuration (6)". Unrecognized configuration section <startup>

My system is debian 10
I have the latest mono-devel installed following these instructions from the mono-project for installing on debian 10:
sudo apt install apt-transport-https dirmngr gnupg ca-certificates
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 3FA7E0328081BFF6A14DA29AA6A19B38D3D831EF
echo "deb https://download.mono-project.com/repo/debian stable-buster main" | sudo tee /etc/apt/sources.list.d/mono-official-stable.list
sudo apt update

Can someone please help me?