App Hub API is disabled on the host project. Even if the
App Hub API has been disabled, any prior service project
attachments to the host project will exist. To resolve this:
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-25 UTC."],[[["\u003cp\u003eThis page provides troubleshooting steps for issues encountered when using App Hub.\u003c/p\u003e\n"],["\u003cp\u003eOne common issue is the inability to attach a service project to a host project.\u003c/p\u003e\n"],["\u003cp\u003eThis issue may arise if the service project is already attached to another host project, requiring detachment before re-attachment.\u003c/p\u003e\n"],["\u003cp\u003eAnother cause is if the App Hub API is disabled on the host project, necessitating either its enabling and subsequent detachment of service projects, or disabling it on the service project, before detaching.\u003c/p\u003e\n"],["\u003cp\u003eInsufficient Identity and Access Management (IAM) permissions on host and service projects can also cause this issue, which can be resolved by granting the \u003ccode\u003eapphub.admin\u003c/code\u003e role.\u003c/p\u003e\n"]]],[],null,["# Troubleshoot App Hub issues\n\nThis page shows you how to resolve issues with App Hub.\n\nYou can't attach a service project to a host project\n----------------------------------------------------\n\nThis issue can occur due to the following reasons:\n\n1. If the service project has existing attachments to a host project. To\n resolve this issue, try the following steps:\n\n - [Remove or detach](/app-hub/docs/set-up-app-hub#add-delete-service-projects) the service project from the existing host project and then [attach the service project to the new host project](/app-hub/docs/set-up-app-hub#add-delete-service-projects).\n - App Hub API is disabled on the host project. Even if the App Hub API has been disabled, any prior service project attachments to the host project will exist. To resolve this:\n - [Enable the App Hub API](/service-usage/docs/enable-disable#enabling) on the host project and detach the service projects from the host project. You can then [attach the service project to the new host project](/app-hub/docs/set-up-app-hub#add-delete-service-projects).\n - [Disable the App Hub API](/service-usage/docs/enable-disable#disabling) on the service project attached to the host project and then detach the service projects from the host project. You can then [attach the service project to the new host project](/app-hub/docs/set-up-app-hub#add-delete-service-projects).\n2. If the appropriate Identity and Access Management (IAM) permissions\n haven't been granted to the host and service projects. To resolve this issue,\n see the [steps to grant the `apphub.admin` role to the principal in the host\n and service projects](/app-hub/docs/set-up-app-hub#enable-app-hub).\n\nRelated information\n-------------------\n\n- To get additional help, see [Get support](/app-hub/docs/support)."]]
