Scanpy Neighborhood Graph Construction Error: "'NoneType' object has no attribute 'split'"

Question

I am running a standard scanpy workflow on a dataset and I reached the neighborhood graph construction.

When I run the line: sc.pp.neighbors(adata, n_neighbors=10, n_pcs=11)

I get the following error: 'NoneType' object has no attribute 'split'

I have followed the workflow from https://scanpy.readthedocs.io/en/stable/tutorials/basics/clustering.html#clustering and this is the first time I have encountered this issue. I am fairly new to scanpy so I'm not sure how to fix this. If it helps, I am running this on Jupyter Notebook, I'm using scanpy version 1.10.2 and anndata version 0.10.8.

I tried changing the n_pcs and run it but that didn't work. I also restarted the kernel and reran it to see if it would work but it didn't.