Multibranch pipeline - gitlab plugin - Unauthorized, cannot start indexing on SCMSourceOwner object

Hi,

followed the description on the gitlab plugin page to setup webhooks when the git repositor receives a push. I can see in the gitlab plugin logs the following output:

WebHook called with url: /project/MyMultiBranchPipelineProject
Notify scmSourceOwner MyMultiBranchPipelineProject about changes for https://<my.git.url>
Unauthorized, cannot start indexing on SCMSourceOwner object

In my pipeline file (in the controller branch), I’ve put in the following code in the properties section:

    pipelineTriggers([
            cron(cronSettings),
            gitlab(secretToken: gitlab_token, triggerOnPush: true)
    ]),
    gitLabConnection('gitlab')

For normal jobs the webhooks are working. I am a bit puzzled why it is not working for the multibranch pipeline job. Does anyone have an idea?

Jenkins setup:
Jenkins: 2.440.1
OS: Windows Server 2022 - 10.0
Java: 17.0.10 - Eclipse Adoptium (OpenJDK 64-Bit Server VM)

NegotiateSSO:105.vf0d0de2a_b_8a_5
Office-365-Connector:4.21.0
active-directory:2.35
antisamy-markup-formatter:162.v0e6ec0fcfcf6
apache-httpcomponents-client-4-api:4.5.14-208.v438351942757
bootstrap5-api:5.3.2-4
bouncycastle-api:2.30.1.77-225.v26ea_c9455fd9
branch-api:2.1152.v6f101e97dd77
build-timeout:1.32
caffeine-api:3.1.8-133.v17b_1ff2e0599
calendar-view:0.3.3
checks-api:2.0.2
cloudbees-folder:6.901.vb_4c7a_da_75da_3
command-launcher:107.v773860566e2e
commons-lang3-api:3.13.0-62.v7d18e55f51e2
commons-text-api:1.11.0-95.v22a_d30ee5d36
credentials:1319.v7eb_51b_3a_c97b_
credentials-binding:657.v2b_19db_7d6e6d
dark-theme:416.v535839b_c4e88
data-tables-api:1.13.8-4
display-url-api:2.200.vb_9327d658781
durable-task:550.v0930093c4b_a_6
echarts-api:5.4.3-4
email-ext:2.104
font-awesome-api:6.5.1-3
git:5.2.1
git-client:4.6.0
git-server:114.v068a_c7cc2574
gitlab-api:5.3.0-91.v1f9a_fda_d654f
gitlab-plugin:1.8.0
gson-api:2.10.1-15.v0d99f670e0a_7
handy-uri-templates-2-api:2.1.8-30.v7e777411b_148
instance-identity:185.v303dc7c645f9
ionicons-api:56.v1b_1c8c49374e
jackson2-api:2.16.1-373.ve709c6871598
jakarta-activation-api:2.0.1-3
jakarta-mail-api:2.0.1-3
javax-activation-api:1.2.0-6
javax-mail-api:1.6.2-9
jaxb:2.3.9-1
jdk-tool:73.vddf737284550
jersey2-api:2.41-133.va_03323b_a_1396
jjwt-api:0.11.5-77.v646c772fddb_0
joda-time-api:2.12.7-29.v5a_b_e3a_82269a_
jquery:1.12.4-1
jquery3-api:3.7.1-2
json-path-api:2.9.0-33.v2527142f2e1d
junit:1259.v65ffcef24a_88
ldap:711.vb_d1a_491714dc
lockable-resources:1243.v346d600eea_24
mailer:463.vedf8358e006b_
matrix-auth:3.2.1
matrix-project:822.824.v14451b_c0fd42
metrics:4.2.21-449.v6960d7c54c69
mina-sshd-api-common:2.12.0-90.v9f7fb_9fa_3d3b_
mina-sshd-api-core:2.12.0-90.v9f7fb_9fa_3d3b_
okhttp-api:4.11.0-172.vda_da_1feeb_c6e
pipeline-build-step:540.vb_e8849e1a_b_d8
pipeline-github-lib:42.v0739460cda_c4
pipeline-graph-analysis:202.va_d268e64deb_3
pipeline-graph-view:224.vef989d141666
pipeline-groovy-lib:704.vc58b_8890a_384
pipeline-input-step:491.vb_07d21da_1a_fb_
pipeline-milestone-step:111.v449306f708b_7
pipeline-model-api:2.2175.v76a_fff0a_2618
pipeline-model-definition:2.2175.v76a_fff0a_2618
pipeline-model-extensions:2.2175.v76a_fff0a_2618
pipeline-rest-api:2.34
pipeline-stage-step:305.ve96d0205c1c6
pipeline-stage-tags-metadata:2.2175.v76a_fff0a_2618
pipeline-utility-steps:2.16.2
plain-credentials:143.v1b_df8b_d3b_e48
plugin-util-api:4.1.0
resource-disposer:0.23
scm-api:683.vb_16722fb_b_80b_
script-security:1326.vdb_c154de8669
scriptler:348.v5d461e205da_a_
snakeyaml-api:2.2-111.vc6598e30cc65
ssh-credentials:308.ve4497b_ccd8f4
sshd:3.322.v159e91f6a_550
structs:337.v1b_04ea_4df7c8
theme-manager:215.vc1ff18d67920
thinBackup:1.18
timestamper:1.26
token-macro:400.v35420b_922dcb_
trilead-api:2.133.vfb_8a_7b_9c5dd1
uno-choice:2.8.1
variant:60.v7290fc0eb_b_cd
workflow-aggregator:596.v8c21c963d92d
workflow-api:1291.v51fd2a_625da_7
workflow-basic-steps:1042.ve7b_140c4a_e0c
workflow-cps:3867.v535458ce43fd
workflow-durable-task-step:1331.vc8c2fed35334
workflow-job:1400.v7fd111b_ec82f
workflow-multibranch:773.vc4fe1378f1d5
workflow-scm-step:415.v434365564324
workflow-step-api:657.v03b_e8115821b_
workflow-support:865.v43e78cc44e0d
ws-cleanup:0.45

I order to solve this issue I turned on logging for the gitlab plugin (like described on the plugin page). Then the plugin reported that there were not sufficient rights for triggering the build. I switch then the webhook url to one which has a user / api token of a jenkins user representing gitlab. That way everything works now.

I still wonder why only multibranch pipeline jobs were affected by this rights issue :frowning:

Alternatively one could hand out build permissions to anonymous user …