If you were using username password for pushing your code, it was working previous but now below error happens:
Username for 'https://github.com': ... Password for 'https://...@github.com': remote: Password authentication is temporarily disabled as part of a brownout. Please use a personal access token instead. remote: Please see https://github.blog/2020-07-30-token-authentication-requirements-for-api-and-git-operations/ for more information.
The reason is that from November 13th, 2020, account passwords when authenticating with the REST API is no longer accepted, and it requires the use of token-based authentication (e.g., a personal access, OAuth, or GitHub App installation token) for all authenticated API operations on GitHub.com.
1. Generate a new token according to below link.
2. Update remote URL
git remote set-url origin https://[NEW_TOKEN]@github.com/[ORGANISATION]/[REPO].git
3. Git pull once
git pull https://[token]@github.com/[ORGANISATION]/[REPO].git
Congratulations! You are good to go now.