The answer to 'drain cleaning not working' is that there are several common causes, including a clogged pipe, a blocked vent, or a problem with the drain trap. Symptoms may include slow draining, standing water, or foul odors. The best solution depends on the cause, but may involve using a plunger, a drain snake, or chemical drain cleaners. If the problem persists, it's best to call a professional plumber to diagnose and resolve the issue.
Trying to unclog a drain yourself with a plunger or drain snake can be effective for minor clogs, but more serious blockages may require specialized tools and expertise. Attempting to use chemical drain cleaners too aggressively can also damage pipes, so it's important to follow the product instructions carefully. If the clog is deep in the pipes or the drain is slow to clear, it's usually best to call in a professional plumber to properly inspect the system and use the right tools and techniques to clear the blockage.