The add-on sign-in flow can be disrupted if the end user has enabled a pop-up
blocker. See the manage pop-up blockers section of the frictionless sign-in
page for more information about how to implement the sign-in flow in the event
that end users enable pop-up blockers.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-28 UTC."],[],[],null,["# Known issues\n\nThis page documents known developer concerns with the\nClassroom add-ons API.\n\nError messages\n--------------\n\nMost errors are covered in the descriptions of specific methods in the\n[reference documentation](/workspace/classroom/reference/rest). Some errors are [specific to add-ons](/workspace/classroom/reference/addons_errors).\n\nIf you're unable to troubleshoot an error on your own, reach out to your Google\ncontacts for support.\n\nCourseWork API compatibility\n----------------------------\n\nSee the [Create attachments from a third-party site](/workspace/classroom/add-ons/get-started/attachments-journey#create-attachments) guide to creating add-on\nattachments through a CourseWork flow.\n\nPop-up blockers\n---------------\n\nThe add-on sign-in flow can be disrupted if the end user has enabled a pop-up\nblocker. See the [manage pop-up blockers section of the frictionless sign-in\npage](/workspace/classroom/add-ons/developer-guides/frictionless-signin#manage_pop-up_blockers) for more information about how to implement the sign-in flow in the event\nthat end users enable pop-up blockers.\n\nMulti-login\n-----------\n\nMulti-login is not supported for add-ons. See the [multi-login section of the\nfrictionless sign-in page](/workspace/classroom/add-ons/developer-guides/frictionless-signin#multi-login) for more information about multi-login issues and\npossible workarounds."]]
