Configure Discovery

Go to discovery.yml file and make sure to modify the discovery.yml to match the JWT_Auth settings as that of the ECommerce:
Located at (/edx/etc/discovery.yml)

JWT_AUTH:
    JWT_ISSUERS:
    -   AUDIENCE: SET-ME-PLEASE
        ISSUER: https://en.school/oauth2
        SECRET_KEY: SET-ME-PLEASE
    JWT_PUBLIC_SIGNING_JWK_SET: '{"keys": [{"kid": "ecommerce-key", "e": "AQAB", "kty": "RSA", "n": "qQtgJs_g_ngLx5SNdxjQliMQs-BatuuSowSdOzxpPHHCXyevGKtlRUr0FHzQ8kfdkH8kfdkHkQ9sxEy3ZNu3UdAZ6JcNROj4UKLMbpbqqAYrSuW3eaaEI1hzKdAKhcgDJyowakC_t4n9XqdvZXllTG6vrKbyh2s5lmYYdu6Z6U9LVT7IiYfqq9dyBKqWhXcZew--lnRYIZaL5aCtsFa_sy4PoDGyXrOJCYsigkrlsigkrltuVXl0BNRtfojzeW2VOfVhiFGEZHIs-_RJ520Z0hRVWEgMpXxpvHLLH3hvEpbKhaP9k_kJIQUCMULSld1Bt4qssOnrnyR7SmET3Vo-hXMcNMzEno6aYQ"}]}'

Note: Follow this link to generate JWT_PUBLIC_SIGNING_JWK_SET

Set AUDIENCE = ECommerce Client Id and SECRET_KEY = ECommerce Client Secret

Now do the OAuth2 Clients settings for Discovery:

Name: discovery
Url: https://en.school:18381
Redirect uri: https://en.school:18381/complete/edx-oidc/
Client id: your-id
Client secret: yout-secret
Client type: Confidential (Web applications)
Logout uri: https://en.school:18381/logout/

Screenshot for reference:

Also make sure to add these clients to the Trusted Clients:

Home › Edx_Oauth2_Provider › Trusted clients

Keep the OAuth Client Id and Client Secret of discovery client created initially into SOCIAL_* settings under this file:

Restart discovery service:

sudo /edx/bin/supervisorctl restart discovery

Note: If the changes do not appear on restart then reboot the machine and test.