Unable to install ubuntu snap in 16.04 LTS

I'm unable to install snap in Ubuntu 16.04, instead, I get the error shown below:

dheer@dheer-Inspiron-3558:~$ sudo snap install notes  
[sudo] password for dheer:  *********

error: cannot perform the following tasks:
- Fetch and check assertions for snap "ubuntu-core" (423) (Get https://assertions.ubuntu.com/v1/assertions/snap-revision/7sS9MbzjeZ87E4IVq3ByrAO8t1YqriNlaX4r7eT5AHYZjzRCa7twTmWU53e6falH: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers))
dheer@dheer-Inspiron-3558:~$ 

Please help?

Solution 1:

You are getting a status code of 423 which indicates the content you are trying to access is locked. This indicates that snap "ubuntu-core" may be in the process of being modified at the time of your attempt to access it. In my case attempts to access assertions.ubuntu.com/v1/assertions/snap-revision lead to a 403 error (Forbidden) as I don't have access.