How to fix invalid_credentials: Login credentials are incorrect in Supabase

const email = userInput.email.trim().toLowerCase();
const password = userInput.password;

const { data, error } = await supabase.auth.signInWithPassword({
  email,
  password,
});

const { data, error } = await supabase.auth.resetPasswordForEmail(email, {
  redirectTo: `${window.location.origin}/auth/callback`,
});

if (error) console.error('Reset error:', error);
else alert('Check your email for password reset link');

// After catching 'invalid_credentials' error
const { data: users } = await supabase
  .from('users') // or your users table name
  .select('id')
  .eq('email', email)
  .single();

if (!users) {
  // User does not exist in system
  console.log('Email not found - user needs to sign up');
} else {
  // User exists but password is wrong
  console.log('Email exists - password is incorrect');
}

// Get current session to see linked identities
const { data: { user } } = await supabase.auth.getUser();

console.log(user?.identities); // Shows OAuth providers used

// If they signed up with GitHub but try password login, explain:
// "You signed up using GitHub. Please sign in with GitHub instead."

import { createClient } from '@supabase/supabase-js';

const supabase = createClient(
  'https://YOUR_PROJECT_ID.supabase.co',
  'YOUR_PUBLIC_ANON_KEY'
);