flowable/flowable-engine · error · FlowableObjectNotFoundException

User '' is not part of group ''.

Error message

User '' is not part of group ''.

What it means

GroupMembershipResource.deleteMembership verifies the user is actually a member of the group via createUserQuery().memberOfGroup(groupId).userId(userId).count() before deleting. When the count is not 1, it throws FlowableObjectNotFoundException (HTTP 404) because the membership does not exist, even though both user and group may individually exist.

Solutions

1. Verify the membership exists before deleting: GET /identity/groups/{groupId}/members and check the userId.
2. Treat 404 from this endpoint as 'already removed' and continue in cleanup scripts.
3. Confirm the exact groupId/userId spelling and casing.

Example fix

// before
client.delete("/identity/groups/sales/members/" + userId); // 404 if not a member
// after
if (fetchMemberIds("sales").contains(userId)) {
    client.delete("/identity/groups/sales/members/" + userId);
}

boolean isMember = client.list("/identity/groups/" + groupId + "/members").stream()
    .anyMatch(m -> userId.equals(m.getUserId()));

try {
    client.delete("/identity/groups/" + groupId + "/members/" + userId);
} catch (HttpClientErrorException e) {
    if (e.getStatusCode() == HttpStatus.NOT_FOUND) {
        log.info("Membership {}#{} already absent", groupId, userId);
    } else throw e;
}

When it happens

Trigger: DELETE /identity/groups/{groupId}/members/{userId} where the user is not a member of the group (or the group does not exist, since getGroupFromRequest runs first).

Common situations: De-provisioning scripts removing memberships that were never created; user already removed by a concurrent request; wrong groupId/userId pairing (member of another group); case-sensitivity mismatch in the user id.

Understand the failure class

Background: Record Not Found Errors: "not found", RecordNotFound, and "was not found" — what they mean and how to fix them — this error's family across 28 libraries.

Related errors

• Could not find a batch with id
• Could not find a job with id ''.
• ${aonfe.getMessage()}
• Batch part with id ' ' does not have a batch part document.
• Batch with id ' ' does not have a batch document.

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/d380db9acf9e39c6. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-rest/src/main/java/org/flowable/rest/service/api/identity/GroupMembershipResource.java:51

 */
@RestController
@Api(tags = { "Groups" }, authorizations = { @Authorization(value = "basicAuth") })
public class GroupMembershipResource extends BaseGroupResource {

    @ApiOperation(value = "Delete a member from a group", tags = { "Groups" }, code = 204)
    @ApiResponses(value = {
            @ApiResponse(code = 204, message = "Indicates the group was found and the member has been deleted. The response body is left empty intentionally."),
            @ApiResponse(code = 404, message = "Indicates the requested group was not found or that the user is not a member of the group. The status description contains additional information about the error.")
    })
    @DeleteMapping("/identity/groups/{groupId}/members/{userId}")
    @ResponseStatus(HttpStatus.NO_CONTENT)
    public void deleteMembership(@ApiParam(name = "groupId") @PathVariable("groupId") String groupId, @ApiParam(name = "userId") @PathVariable("userId") String userId) {

        Group group = getGroupFromRequest(groupId);

        // Check if user is not a member of group since API does not return typed exception
        if (identityService.createUserQuery().memberOfGroup(group.getId()).userId(userId).count() != 1) {
            throw new FlowableObjectNotFoundException("User '" + userId + "' is not part of group '" + group.getId() + "'.", null);
        }

        identityService.deleteMembership(userId, group.getId());
    }
}

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