Why am I not able to create a new trust in Active Directory?

To create a new trust in Active Directory, here are some steps to follow:

1. In the Active Directory Domains and Trusts snap-in window, click Action and then select New Trust to open the New Trust Wizard.
2. Follow the instructions and enter the required information for the trust.
3. On the Trust Type page, select External Trust to create a trust with another organization, or select Forest Trust to create a trust with another forest in your organization.
4. On the Sides of Trust page, select either one-way incoming or one-way outgoing to create a one-way trust.
5. On the Direction of Authentication page, select Incoming or Outgoing to select the direction of authentication.
6. On the Outgoing Trust Authentication Level page, select one of the authentication levels for the outgoing trust.
7. On the Trust Name page, enter a unique name for the trust.
8. If you select Forest Trust on the Trust Type page, you will be asked for credentials for the other forest.
9. On the Permissions section, choose the appropriate authentication and verify it.
10. On the Name Suffix Routing page, specify the name suffix for which this trust will route traffic, and click Next.
11. On the Completing the New Trust Wizard, click Next to continue with the specified settings and then click Finish.