Thanks for trying it. Can you send me your terminal session? Here is how it should look like:
$ conda create -n lf3 -c conda-forge lfortran jupyter python=3.8
...
$ conda activate lf3
$ jupyter console --kernel="fortran"
Run with XEUS 1.0.4
Jupyter console 6.4.0
LFortran 0.14.0
Jupyter kernel for Fortran
In [1]: 4+4
Out[1]: 8
In [2]: integer :: x
In [3]: x = 5
In [4]: x-2
Out[4]: 3