3688834 - "You have not been successfully logged on. Logon to the service instance has failed." error messages when trying to access a customizing tenant from ADT

"You have not been successfully logged on. Logon to the service instance has failed." error message encountered while accessing the customizing tenant via ABAP Development Tools (ADT) even after assigning a developer role. 

• ADT
• Eclipse

1. Attempt to log in to the customizing tenant using ABAP Development Tools (ADT).
2. Observe the error message: "You have not been successfully logged on. Logon to the service instance has failed."

Please follow these recommended steps: 

• In ADT, use the "Copy Logon URL to Clipboard" button and paste the URL into a new incognito browser window to complete the login.

• Verify that your instance is active and not in a hibernate state.

• Check if the Fiori launchpad is reachable by trying to open it directly in your browser.

If these procedures still ends in the error, you can try the following: 

• Create a new custom role based on the business role template SAP_BR_APPL_SUP_ENG_DEV_SUP
• Assign this new custom role to the relevant user
• Retry the ADT logon

The SAP business role SAP_BR_APPL_SUP_ENG_DEV_SUP is intended for application support engineers. It grants them access to diagnostic tools such as ADT, ABAP debugging, and the ability to review ABAP short dumps. Critically, this role does not include permissions for any ABAP development activities.

As a general principle, customizing tenants are not designed to support ABAP development. All development work must be performed in the development tenant. Consequently, the required development catalogs are not available in customizing tenants. 

SAP Note 3254529 - ADT: Error occurred during the service instance logon

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