diff --git a/changelog.d/5909.misc b/changelog.d/5909.misc
new file mode 100644
index 000000000000..73e35cc48d4b
--- /dev/null
+++ b/changelog.d/5909.misc
@@ -0,0 +1 @@
+Fix error message which referred to public_base_url instead of public_baseurl.
diff --git a/synapse/config/emailconfig.py b/synapse/config/emailconfig.py
index 36d01a10af70..f83c05df441f 100644
--- a/synapse/config/emailconfig.py
+++ b/synapse/config/emailconfig.py
@@ -115,7 +115,7 @@ def read_config(self, config, **kwargs):
                     missing.append("email." + k)
 
             if config.get("public_baseurl") is None:
-                missing.append("public_base_url")
+                missing.append("public_baseurl")
 
             if len(missing) > 0:
                 raise RuntimeError(
diff --git a/synapse/rest/well_known.py b/synapse/rest/well_known.py
index 5e8fda4b6575..20177b44e7cd 100644
--- a/synapse/rest/well_known.py
+++ b/synapse/rest/well_known.py
@@ -34,7 +34,7 @@ def __init__(self, hs):
         self._config = hs.config
 
     def get_well_known(self):
-        # if we don't have a public_base_url, we can't help much here.
+        # if we don't have a public_baseurl, we can't help much here.
         if self._config.public_baseurl is None:
             return None