Fitting a Dipole

I’ve been getting an error when i try to fit a dipole . It says

File ~\Anaconda3\lib\site-packages\mne\bem.py:1466, in _read_bem_solution_fif(fname)
1464 tag = find_tag(f, bem_node, FIFF.FIFF_BEM_APPROX)
1465 if tag is None:
→ 1466 raise RuntimeError(‘No BEM solution found in %s’ % fname)
1467 method = tag.data[0]
1468 tag = find_tag(fid, bem_node, FIFF.FIFF_BEM_POT_SOLUTION)

RuntimeError: No BEM solution found in E:\MRI\sample\bem\sample-head.fif

Thanks
Krushi