### [Invalid Signature or Credentials](https://wpmailsmtp.com/docs/invalid-signature-or-credentials-amazon-ses/)

**Published:** May 17, 2026
**Author:** David Ozokoye

**Content:**

**Note**: This guide applies to the [Amazon SES mailer](https://wpmailsmtp.com/docs/how-to-set-up-the-amazon-ses-mailer-in-wp-mail-smtp/ "Amazon SES") in WP Mail SMTP.

## What This Error Means

AWS rejected the request because the Access Key ID or Secret Access Key in WP Mail SMTP is wrong, or the IAM user doesn’t have permission to use SES.

## Common Causes

- The **Closest Region** in WP Mail SMTP doesn’t match the AWS region where SES is configured
- Access Key ID or Secret Access Key entered incorrectly (common, since the Secret Access Key is long and easy to truncate when copying)
- IAM user doesn’t have the `AmazonSESFullAccess` permission policy
- Access keys were deactivated or deleted in AWS IAM
- Using keys from a different AWS account than the one where SES was set up

## How to Fix

Here is the complete step-by-step guide to resolving the error.

### Step 1: Check the Closest Region

A wrong region causes this error even with correct credentials.

Start by navigating to **WP Mail SMTP » Settings** and scroll to the **Amazon SES** section.

![WP Mail SMTP settings](https://wpmailsmtp.com/wp-content/uploads/2023/08/wp-mail-smtp-settings.png)After that, look at the **Closest Region** dropdown.

![Closest Region setting in WP Mail SMTP](https://wpmailsmtp.com/wp-content/uploads/2022/02/closest-region-setting.png)This must match the region where your SES account and identities are set up (for example, **US East (N. Virginia)**, **EU (Ireland)**).

If you’re not sure which region your SES is in, go to the AWS Console, open **Amazon SES**, and check the region shown in the top-right corner of the page.

If the regions don’t match, select the correct one in WP Mail SMTP.

Click **Save Settings**.

Go to **WP Mail SMTP » Tools**, click the **Email Test** tab, and click **Send Email**.

If the error is gone, you’re done. If it persists, continue to Step 2.

### Step 2: Check the IAM User’s Permissions

If the region is correct, the IAM user may be missing the required permission.

Log in to the **AWS Console** (console.aws.amazon.com). Check the account name in the top-right corner to confirm you’re in the right account.

Once you’re logged in, search for **IAM** in the top search bar.

![AWS Console with IAM typed in the search bar](https://wpmailsmtp.com/wp-content/uploads/2026/05/aws-console-search-iam.png)After that, select **IAM** in the search results.

![IAM search result in the AWS Console](https://wpmailsmtp.com/wp-content/uploads/2026/05/aws-console-click-iam-result.png)In the IAM dashboard, click **Users** from the left sidebar.

![IAM sidebar showing Users link](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-sidebar-click-users.png)Click the name of the user you created for WP Mail SMTP (it may be named something like `yourdomain_wpmailsmtp`). If you don’t see a user, skip to **Step 4**.

![IAM Users list showing user names](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-users-list-click-user.png)Click the **Permissions** tab. Look for `AmazonSESFullAccess` in the policies list. If it’s there, the permissions are fine. Continue to **Step 3**.

![Permissions tab showing AmazonSESFullAccess policy](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-user-permissions-policy.png)If it’s not there, click the **Add permissions** dropdown button.

![Add permissions dropdown button on the Permissions tab](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-user-click-add-permissions-dropdown.png)Click **Add permissions** in the dropdown menu.

![Add permissions dropdown showing Add permissions and Create inline policy options](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-user-click-add-permissions-menu-item.png)Select **Attach policies directly**.

![Attach policies directly option on the Set permissions page](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-set-permissions-attach-directly.png)Then type `AmazonSESFullAccess` in the search bar and select the checkbox next to it.

![AmazonSESFullAccess policy selected in the search results](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-set-permissions-search-select-policy.png)After that, click **Next** to continue.

![Next button on the Set permissions page](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-set-permissions-click-next.png)Click **Add permissions** to save your changes.

![Add permissions button on the review page](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-review-click-add-permissions.png)To test it out, send a test email. For this, go to **WP Mail SMTP » Tools**, click the **Email Test** tab, and click **Send Email**.

![Email test tab](https://wpmailsmtp.com/wp-content/uploads/2024/10/test-email-tab-1024x1002.png)If the error is gone, then you’re done. However, if it persists, continue to Step 3.

### Step 3: Create a New Access Key

AWS does not let you view the Secret Access Key after it’s created, so you can’t re-copy an existing one. The fix is to create a new key pair.

In the **AWS Console**, go to **IAM » Users** and click your user’s name. Click the **Security credentials** tab.

![Security credentials tab on user detail page](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-user-click-security-credentials-tab.png)Scroll down to the **Access keys** section.

![Access keys section showing status and Create access key button](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-user-access-keys-section.png)If you see an existing key with Status **Inactive**, click **Actions » Activate** to re-enable it. If the key is **Active** but the error persists, continue below to create a new one.

Click the **Create access key** button.

![Create access key button in the Access keys section](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-user-click-create-access-key.png)Select **Other** as the use case.

![Create access key use case selection — select Other](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-create-access-key-select-other.png)Click **Next**.

![Next button in the Create access key wizard](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-create-access-key-click-next.png)Click **Create access key**.

![Create access key button on the description tag page](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-create-access-key-click-create.png)Copy both the **Access Key ID** and the **Secret Access Key**. The Secret Access Key is only shown once, so save it somewhere secure before closing this page.

Go to **WP Mail SMTP » Settings** and scroll to the **Amazon SES** section.

Paste the new **Access Key ID** and **Secret Access Key** into their fields.

![Access Key ID and Secret Access Key fields in WP Mail SMTP](https://wpmailsmtp.com/wp-content/uploads/2026/05/access-key-and-secret-access-key.png)Verify the **Closest Region** matches your SES region.

Click **Save Settings**.

Go to **WP Mail SMTP » Tools**, click the **Email Test** tab, and click **Send Email**.

### Step 4: If You Don’t Have an IAM User Yet

If you don’t see a user for WP Mail SMTP in the IAM Users list, create one:

In the **AWS Console**, go to **IAM » Users**.

Click the **Create user** button.

![Users list with Create user button](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-users-list-click-create-user.png)Enter a user name (recommended: `yourdomain_wpmailsmtp`, e.g. `example_wpmailsmtp`).

![User name entry field in Create user wizard](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-create-user-enter-name.png)Click **Next**.

![Next button on the Create user wizard](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-create-user-click-next.png)Select **Attach policies directly**.

![Attach policies directly option on the Set permissions page](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-create-user-attach-directly.png)Type `AmazonSESFullAccess` in the search bar and select the checkbox next to it.

![AmazonSESFullAccess policy selected in the Create user wizard](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-create-user-search-select-policy.png)Click **Next**.

![Next button on the Set permissions page](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-create-user-click-next-permissions.png)Review the details, then click **Create user**.

![Create user button on the review page](https://wpmailsmtp.com/wp-content/uploads/2026/05/iam-create-user-click-create.png)Now follow **Step 3** above to create an Access Key for this new user.

## Notes

- AWS only shows the Secret Access Key once when you create it. If you’ve lost it, create a new key (Step 3).
- Some AWS regions are not enabled by default (Africa/Cape Town, Asia Pacific/Hong Kong, Asia Pacific/Jakarta, Europe/Milan, Middle East/Bahrain). If your SES is in one of these regions, you must manually enable the region in your AWS account settings first.

That’s It! You now know how to fix the ‘Invalid Signature or Credentials’ error in Amazon SES and get your emails sending again through WP Mail SMTP.

**Categories:** Amazon SES Errors, Error Library

---