Common Issues

Connection issues

OAuth authorization fails or returns an error

This usually means something went wrong during the Snowflake OAuth flow. Common causes:

• Your Snowflake account URL is incorrect or the account is inactive

• Your browser is blocking pop-ups or third-party cookies required for the OAuth redirect

• The Snowflake user you're logging in with doesn't have a default role assigned

Things to try:

• Ensure you're logging into the correct Snowflake account

• Allow pop-ups for Coupler.io in your browser settings

• Check that your Snowflake user has a default role set (e.g., SYSADMIN or a custom role with the required privileges)

• Try disconnecting and reconnecting the Snowflake account in Coupler.io

Data flow fails because the warehouse is suspended

Snowflake warehouses can be suspended (paused) to save credits. If the warehouse assigned to your user or role is suspended and auto-resume is disabled, Coupler.io won't be able to execute queries.

To fix this:

• Enable auto-resume on the warehouse so it starts automatically when Coupler.io connects

• Alternatively, manually resume the warehouse in the Snowflake console before running the data flow

You can enable auto-resume with: ALTER WAREHOUSE your_warehouse SET AUTO_RESUME = TRUE;

Connection times out during the data flow run

A timeout during the run (not at the OAuth step) can indicate the warehouse is too small for the data volume, or that Snowflake is experiencing transient issues.

• Try running the data flow again — transient timeouts often resolve themselves

• If the issue persists, consider scaling up the warehouse size temporarily for the initial load

• Check the Snowflake query history in the Snowflake console for more details on what failed

Data issues

Append mode breaks after a source schema change

When using Append mode, Coupler.io writes new rows into the existing table structure. If your source adds new columns (for example, a new metric in your ad platform), Snowflake won't know about them and the run may fail.

To fix this, manually ALTER TABLE in Snowflake to add the new column(s) before the next run. After that, Coupler.io will populate them normally.

Data types are wrong in the destination table

Coupler.io detects and enforces column types automatically. However, if the table already exists with different column types from a previous run or manual creation, there can be a mismatch.

• If you're using Replace mode, try dropping the existing table and letting Coupler.io recreate it cleanly on the next run

• If you're using Append mode, check that the existing table's column types match what Coupler.io is trying to write

Data flow fails with an identifier or naming error

Snowflake treats unquoted identifiers as uppercase by default. If your table or column names contain mixed case or special characters, they may need to be quoted in Snowflake.

• Let Coupler.io create the table from scratch (using Replace mode on a new table) to avoid naming conflicts

• If you pre-created the table manually, make sure the column names match exactly what Coupler.io expects — check case sensitivity

Permission errors

Permission denied when creating a schema or table

The Snowflake role associated with your connected account doesn't have enough privileges. Make sure the role has:

• USAGE on the target warehouse

• USAGE on the target database

• USAGE and CREATE TABLE on the target schema

• INSERT on the target table

You can grant these with:

GRANT USAGE ON WAREHOUSE your_warehouse TO ROLE your_role;
GRANT USAGE ON DATABASE your_database TO ROLE your_role;
GRANT USAGE ON SCHEMA your_database.your_schema TO ROLE your_role;
GRANT CREATE TABLE ON SCHEMA your_database.your_schema TO ROLE your_role;
GRANT INSERT ON ALL TABLES IN SCHEMA your_database.your_schema TO ROLE your_role;

If you want Coupler.io to create new tables automatically, the role needs CREATE TABLE on the schema — not just INSERT on existing tables.