snowflake.connector.errors.ProgrammingError: 250001 (08001): Failed to connect to DB

TL;DR: The driver cannot establish the session: wrong account identifier, bad credentials, or blocked network. Use the full account identifier ([org]-[account]), verify the password, and make sure your firewall allows Snowflake.

snowflake.connector.errors.ProgrammingError: 250001 (08001): Failed to connect to DB: [account].snowflakecomputing.com:443

Fix it

1. Use the right account format: account='[orgname]-[accountname]' (new format) or the legacy locator with region/cloud if needed. Expected: matches what the Snowflake UI shows in your URL.
2. Verify user and password by logging into the web UI with the same pair. Expected: logs in.
3. Test the network: curl -sI your Snowflake account URL with a 10 second timeout. Expected: HTTP 200. A fail means firewall/proxy.
4. Retry connect() with the corrected parameters. Expected: connection opens.

When this applies

• connect() raises ProgrammingError 250001.

When it doesn't

• The import itself fails: native dependency problem, different skill.
• Queries fail after connecting: warehouse/role/permission issue.

Compatibility

• snowflake-connector-python 2.x/3.x.

Why it happens

250001 is the generic "could not connect" bucket: DNS/account typos, wrong passwords, and blocked egress all land here, so check all three.

Edge cases

• SSO/OAuth users must pass authenticator='externalbrowser' or 'oauth' with a token, not a password.
• PrivateLink accounts use a different hostname; the public one will not resolve.

Reported in GitHub (gh:snowflakedb/snowflake-connector-python#2951): 250001 (08001) hardcoded errno for auth failures (snowflakedb/snowflake-connector-python#2951). The verified fix: Asked on Stack Overflow by developers getting 250001 Failed to connect to DB from snowflake-connector-python. The verified answer: the account identifier, credentials, or network path is wrong, so fix the account name format, verify user/password, and allowlist Snowflake IPs. Source: the linked Stack Overflow thread. Source: https://github.com/snowflakedb/snowflake-connector-python/pull/2951 Thread ref: gh:snowflakedb/snowflake-connector-python#2951