Unable to Upgrade to Ubuntu 18.04 From Ubuntu 17.10

I’m trying to upgrade my Ubuntu release from 17.10 to 18.04 without success.

do-release-upgrade is returning the following error:

Checking package manager  Can not upgrade   Your python3 install is corrupted. Please fix the '/usr/bin/python3'  symlink. 

I removed all my update-alternatives configuration for python, then I tried to reinstall python3 but it didn’t work.

I tried also to completely remove python3 and then install it again without fixing the issue.

Just for your information /usr/bin/python3 symlink seems to work fine:

neoben@neoben-samsung:~$   /usr/bin/python3 Python 3.6.3 (default, Oct  3 2017, 21:45:48)  [GCC 7.2.0] on linux Type "help", "copyright", "credits" or "license" for more information. >>>  

Do you have any suggestion to solve the problem?

Thanks!