Cannot save notebook with particular name

[ghuname]

I created a new notebook. It got a name Untitled4.ipynb. I saved it and it is saved.
Now I renamed the notebook to vip-cempresso.ipynb. When I tried to save, I got an error:
File Save Error for vip-cempresso.ipynb
Failed to fetch

From now on, I cannot save the notebook, I cannot rename it, I can only close it.
On file system I can see file vip-cempresso.ipynb.

If i try to open it in jupyter I get an error:
File Load Error for vip-cempresso.ipynb
Failed to fetch

If I rename file vip-cempresso.ipynb to abc.ipynb I can open the file.

What is wrong with file name vip-cempresso.ipynb?

jupyter lab --version
0.35.4

PRETTY_NAME="CentOS Linux 7 (Core)"

Node v6.14.3

Google Chrome Version 71.0.3578.98 (Official Build) (64-bit) on windows 10 machine connected remote to jupyter lab on centos.