Regarding package error

[vishal623]

Hello,

When I am trying to open foren6 in Ubuntu 20.04, it shows me the following error:

vishal@lenovo-z51-70:~$ foren6
foren6: error while loading shared libraries: libQtGui.so.4: cannot open shared object file: No such file or directory

Day before yesterday, it is perfectly working.

When I tried to install a particular framework. It said the following things

vishal@lenovo-z51-70:~$ sudo apt-get install libqtgui4:amd64
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package libqtgui4 is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'libqtgui4' has no installation candidate

Need a solution.