Trouble With GitHub Enterprise Repo

Version report

Jenkins and plugins versions report:

Jenkins: 2.289
OS: Linux - 4.14.152-127.182.amzn2.x86_64
---
cloudbees-folder:6.15
docker-commons:1.17
jdk-tool:1.5
jackson2-api:2.12.3
script-security:1.76
command-launcher:1.5
structs:1.22
pipeline-stage-view:2.19
workflow-step-api:2.23
docker-workflow:1.26
scm-api:2.6.4
workflow-api:2.42
junit:1.49
bouncycastle-api:2.20
antisamy-markup-formatter:2.1
token-macro:2.15
pipeline-build-step:2.13
build-timeout:1.20
credentials:2.3.18
plain-credentials:1.7
pipeline-model-api:1.8.4
ssh-credentials:1.18.2
credentials-binding:1.24
timestamper:1.12
workflow-support:3.8
github-api:1.123
durable-task:1.35
pipeline-milestone-step:1.3.2
workflow-durable-task-step:2.38
jsch:0.1.55.2
matrix-project:1.18
resource-disposer:0.15
ws-cleanup:0.39
git:4.7.1
ace-editor:1.1
git-client:3.7.1
jquery-detached:1.2.1
workflow-scm-step:2.12
workflow-cps:2.90
github:1.33.1
workflow-job:2.40
git-server:1.9
display-url-api:2.3.4
mailer:1.34
apache-httpcomponents-client-4-api:4.5.13-1.0
workflow-cps-global-lib:2.18
workflow-basic-steps:2.23
gradle:1.36
pipeline-input-step:2.12
pipeline-stage-step:2.5
pipeline-graph-analysis:1.10
pipeline-rest-api:2.19
mapdb-api:1.0.9.0
handlebars:3.0.8
momentjs:1.1.1
branch-api:2.6.3
pipeline-model-extensions:1.8.4
workflow-multibranch:2.23
authentication-tokens:1.4
pipeline-stage-tags-metadata:1.8.4
pipeline-model-declarative-agent:1.1.1
pipeline-model-definition:1.8.4
workflow-aggregator:2.6
aws-java-sdk:1.11.995
pipeline-github-lib:1.0
matrix-auth:2.6.6
pam-auth:1.6
snakeyaml-api:1.27.0
mission-control-view:0.9.16
subversion:2.14.0
variant:1.4
aws-credentials:1.29
ec2:1.57
github-branch-source:2.10.2
slack:2.47
lockable-resources:2.10
trilead-api:1.0.13
ssh-slaves:1.31.7
ghprb:1.42.2
ansicolor:0.7.5
ldap:2.6
embeddable-build-status:2.0.3
email-ext:2.82
node-iterator-api:1.5.0
metrics:4.0.2.7
plugin-util-api:2.1.0
github-checks:1.0.12
simple-theme-plugin:0.6
okhttp-api:3.14.9
extended-read-permission:3.2
cloudbees-disk-usage-simple:0.10
build-user-vars-plugin:1.7
font-awesome-api:5.15.2-2
echarts-api:5.1.0-2
bootstrap4-api:4.6.0-3
prometheus:2.0.10
checks-api:1.7.0
popper-api:1.16.1-2
jjwt-api:0.11.2-9.c8b45b8bb173
jquery3-api:3.6.0-1
pipeline-aws:1.43
sshd:3.0.3
saml:2.0.3

What Operating System are you using (both controller, and any agents involved in the problem)?

Amazon Linux 2

Reproduction steps

I'm sorry, but I'm not sure how to reproduce this. PR integration has stopped working for one of our repos without me making any changes to Jenkins settings or pipelines. I would like to know how to debug this. We are very happy with the plugin, and aside from company IP, I'll be happy to provide more info as needed. We are working with GitHub Enterprise 2.20.14.

Results

Expected result:

I expected the pipeline to be triggered by a new commit to the PR branch.

Actual result:

Nothing happens.

jenkinsci / ghprb-plugin