If the LDAP uid attribute does not use an email format - the default format for the Okta username (user.login) - then user validation may fail with an error message:

Please review the form to correct the following errors:

• Example username: Username must be in the form of an email address 
• The Example username field must follow the format restrictions configured for the Okta username attribute (user.login)

• Lightweight Directory Access Protocol (LDAP)
• User ID
• Format Restrictions

When modifications are made to an existing Lightweight Directory Access Protocol (LDAP) integration, a test user must be validated before the configuration can be saved. This is meant to protect the LDAP Integration, but it can also cause confusing problems with its design.

To resolve the above error, change the format restrictions for the Okta username.

1. Go to Admin > Directory > Profile Editor, and click the Okta (default) user type.

2. On the row for the Username attribute, click the Info icon. 

3. Next to Format restrictions, click the dropdown and change the restriction to None.

4. Click Save Attribute.
5. Go to Admin > Directory > Directory Integrations > [LDAP] > Provisioning > Integration, and test the validation field with a known user UID.
6. The user should validate.

NOTE: This change may be reverted directly after validation and must not be permanently modified.