diff --git a/openedx_webhooks/info.py b/openedx_webhooks/info.py
index be0cd8e3..9e011def 100644
--- a/openedx_webhooks/info.py
+++ b/openedx_webhooks/info.py
@@ -157,7 +157,10 @@ def get_jira_server_info(jira_nick: str) -> JiraServer:
     Given a Jira nickname, get the JiraServer info about it.
     """
     jira_info = get_jira_info()
-    jira_server = jira_info[jira_nick.lower()]
+    try:
+        jira_server = jira_info[jira_nick.lower()]
+    except KeyError:
+        raise KeyError(f"No Jira server configured with nick {jira_nick!r}")
     return jira_server
 
 
@@ -355,4 +358,7 @@ def jira_details_for_pr(jira_nick: str, pr: PrDict) -> tuple[str, str]:
             details.update(repo_info)
             break
 
-    return details["project"], details["type"]
+    try:
+        return details["project"], details["type"]
+    except KeyError:
+        raise ValueError(f"No Jira project mapping for {repo_name!r}: {details=}")
diff --git a/tests/fake_jira.py b/tests/fake_jira.py
index 7d475ee3..efd555ef 100644
--- a/tests/fake_jira.py
+++ b/tests/fake_jira.py
@@ -3,7 +3,7 @@
 import dataclasses
 import itertools
 from dataclasses import dataclass, field
-from typing import Dict, List, Optional, Set
+from typing import Dict, Optional, Set
 
 from . import faker
 
diff --git a/tests/repo_data/openedx/openedx-webhooks-data/test-jira-info.yaml b/tests/repo_data/openedx/openedx-webhooks-data/test-jira-info.yaml
index ad6fc5e5..1d90719e 100644
--- a/tests/repo_data/openedx/openedx-webhooks-data/test-jira-info.yaml
+++ b/tests/repo_data/openedx/openedx-webhooks-data/test-jira-info.yaml
@@ -6,6 +6,12 @@ Test1:
     token: asdasdasdasdasd
     mapping: https://raw.githubusercontent.com/test1/dot-github/HEAD/jira-mapping.yaml
     description: the private Test1 Jira
+Test2:
+    server: https://test2.atlassian.net
+    email: jira-user@test2.com
+    token: asdasdasdasdasd
+    mapping: https://raw.githubusercontent.com/test2/dot-github/HEAD/jira-mapping.yaml
+    description: the private Test2 Jira
 AnotherOrg:
     server: https://anotherorg.atlassian.net
     email: jira-user@anotherorg.com
diff --git a/tests/repo_data/test2/dot-github/jira-mapping.yaml b/tests/repo_data/test2/dot-github/jira-mapping.yaml
new file mode 100644
index 00000000..43dafa2f
--- /dev/null
+++ b/tests/repo_data/test2/dot-github/jira-mapping.yaml
@@ -0,0 +1,6 @@
+# Mapping from repo to Jira.
+defaults:
+  type: Task
+repos:
+  - name: nedbat/*
+    project: NEDBAT
diff --git a/tests/test_pull_request_opened.py b/tests/test_pull_request_opened.py
index b1f2df0e..6efc2358 100644
--- a/tests/test_pull_request_opened.py
+++ b/tests/test_pull_request_opened.py
@@ -416,7 +416,7 @@ def test_jira_labelling_later(fake_github, fake_jira, fake_jira2):
     jira_issue = fake_jira2.issues[jira_id.key]
     assert jira_issue.summary == "Yet another PR"
 
-def test_bad_jira_labelling(fake_github, fake_jira, fake_jira2):
+def test_bad_jira_labelling_no_server(fake_github, fake_jira, fake_jira2):
     # What if the jira: label doesn't match one of our configured servers?
     pr = fake_github.make_pull_request("openedx", user="nedbat", title="Ned's PR")
     pr.set_labels(["jira:bogus"])
@@ -424,5 +424,14 @@ def test_bad_jira_labelling(fake_github, fake_jira, fake_jira2):
         pull_request_changed(pr.as_json())
     assert len(exc_info.value.exceptions) == 1
     exc = exc_info.value.exceptions[0]
-    assert isinstance(exc, KeyError)
-    assert exc.args == ("bogus",)
+    assert exc.args == ("No Jira server configured with nick 'bogus'",)
+
+def test_bad_jira_labelling_no_repo_map(fake_github, fake_jira, fake_jira2):
+    # What if the jira: label is good, but the repo has no mapping to a project?
+    pr = fake_github.make_pull_request("openedx", user="nedbat", title="Ned's PR")
+    pr.set_labels(["jira:test2"])
+    with pytest.raises(ExceptionGroup) as exc_info:
+        pull_request_changed(pr.as_json())
+    assert len(exc_info.value.exceptions) == 1
+    exc = exc_info.value.exceptions[0]
+    assert exc.args[0].startswith("No Jira project mapping for 'openedx/a-repo':")