How to fix fatal: repository 'https://github.com/user/repo.git/' not found in Git

First, double-check that the repository URL is spelled correctly and exists.

# Check your current remote URL
git remote -v

# You should see output like:
# origin  https://github.com/username/repository.git (fetch)
# origin  https://github.com/username/repository.git (push)

Common URL mistakes to check:
- Username typos: github.com/usrname/repo vs github.com/username/repo
- Repository name typos: Repository names are case-sensitive on some platforms
- Wrong organization: Using personal namespace instead of organization name
- Missing .git suffix: Some operations require the .git extension

Visit the repository URL in your browser to confirm it exists. If you get a 404 page, the URL is wrong or the repository doesn't exist.

If the repository is private, you must have explicit access granted by the owner or organization.

To verify your access:
1. Log into the Git hosting service (GitHub, GitLab, Bitbucket, etc.)
2. Navigate to the repository URL directly
3. If you can see the repository, you have access; if you get a 404, you don't

For GitHub:
- Check if you're a collaborator on the repository
- If it's an organization repo, verify your team has access
- Ask the repository owner to add you as a collaborator

For organization repositories:
Some organizations restrict access to members only. Contact your organization administrator if you believe you should have access.

Ensure you're properly authenticated. The method depends on whether you're using HTTPS or SSH.

For HTTPS URLs:

# GitHub - Use a Personal Access Token (PAT)
# Passwords no longer work as of August 2021

# Set up credential caching (stores credentials temporarily)
git config --global credential.helper cache

# Or on macOS, use the keychain
git config --global credential.helper osxkeychain

# On Windows, use the credential manager
git config --global credential.helper wincred

# Try cloning - you'll be prompted for username and PAT
git clone https://github.com/username/repository.git

Creating a Personal Access Token on GitHub:
1. Go to GitHub Settings > Developer settings > Personal access tokens
2. Click "Generate new token (classic)"
3. Select the repo scope for full repository access
4. Copy the token and use it as your password when prompted

For SSH URLs:

# Check if you have an SSH key
ls -la ~/.ssh/id_rsa.pub  # or id_ed25519.pub

# Test SSH connection to GitHub
ssh -T [email protected]

# Expected success message:
# "Hi username! You've successfully authenticated..."

If SSH test fails, add your SSH key to your Git hosting account.

Old or incorrect cached credentials can cause authentication to silently fail, resulting in a "not found" error.

On macOS:

# Remove GitHub credentials from Keychain
# Open Keychain Access app and search for "github.com"
# Or use command line:
git credential-osxkeychain erase
host=github.com
protocol=https
# Press Enter twice

# Then try your git operation again - you'll be prompted for new credentials

On Windows:

# Open Credential Manager from Control Panel
# Or use:
git credential-manager-core erase
host=github.com
protocol=https
# Press Enter twice

# Alternative: Uninstall and reinstall credential manager
git credential-manager-core uninstall
git credential-manager-core install

On Linux:

# If using credential cache
git credential-cache exit

# If credentials are stored in a file
# Check and edit ~/.git-credentials

# Remove the stored credential for the specific host
git credential reject
host=github.com
protocol=https
# Press Enter twice

If authentication isn't working with one method, try switching to the other.

Switch from HTTPS to SSH:

# View current remote
git remote -v

# Change to SSH URL
git remote set-url origin [email protected]:username/repository.git

# Verify the change
git remote -v

Switch from SSH to HTTPS:

# Change to HTTPS URL
git remote set-url origin https://github.com/username/repository.git

# Verify the change
git remote -v

URL formats for different services:

| Service | HTTPS | SSH |
|---------|-------|-----|
| GitHub | https://github.com/user/repo.git | [email protected]:user/repo.git |
| GitLab | https://gitlab.com/user/repo.git | [email protected]:user/repo.git |
| Bitbucket | https://bitbucket.org/user/repo.git | [email protected]:user/repo.git |

You might be authenticated with a different account than the one that has access.

Check your Git configuration:

# Check global user configuration
git config --global user.name
git config --global user.email

# Check local repository configuration
git config user.name
git config user.email

For SSH, check which key is being used:

# List loaded SSH keys
ssh-add -l

# Test GitHub connection with verbose output
ssh -vT [email protected]

If you have multiple GitHub accounts:
You may need to configure SSH to use different keys for different accounts. Create or edit ~/.ssh/config:

# Personal account
Host github.com-personal
  HostName github.com
  User git
  IdentityFile ~/.ssh/id_rsa_personal

# Work account
Host github.com-work
  HostName github.com
  User git
  IdentityFile ~/.ssh/id_rsa_work

Then use the custom host in your remote URL:

git remote set-url origin [email protected]:company/repo.git

If you have two-factor authentication enabled, you must use a Personal Access Token (PAT) or SSH key - regular passwords won't work.

For HTTPS with 2FA:
1. Generate a Personal Access Token (PAT) as described in Step 3
2. Use the PAT instead of your password when prompted
3. Consider using a credential helper to store the token

For SSH with 2FA:
SSH authentication with keys works normally with 2FA enabled. If you're not already using SSH, consider switching:

# Generate a new SSH key if needed
ssh-keygen -t ed25519 -C "[email protected]"

# Start the SSH agent
eval "$(ssh-agent -s)"

# Add your key to the agent
ssh-add ~/.ssh/id_ed25519

# Copy your public key
cat ~/.ssh/id_ed25519.pub
# Add this to your GitHub account under Settings > SSH keys