diff --git a/api-tests/tests/monitoring-instances.spec.ts b/api-tests/tests/monitoring-instances.spec.ts
index fe1707d7..cb8b505d 100644
--- a/api-tests/tests/monitoring-instances.spec.ts
+++ b/api-tests/tests/monitoring-instances.spec.ts
@@ -278,7 +278,7 @@ test('patch monitoring instance type fails on missing key', async ({ request })
 
   const getJson = await updated.json()
 
-  expect(getJson.message).toMatch('pmm key is required')
+  expect(getJson.message).toMatch('Pmm key is required')
 })
 
 test('create monitoring instance failures', async ({ request }) => {
diff --git a/api/marshal.go b/api/marshal.go
index 1d7d3a87..954747bc 100644
--- a/api/marshal.go
+++ b/api/marshal.go
@@ -5,7 +5,7 @@ import (
 	"unicode"
 )
 
-// MarshalJSON capitalizes Error.Message and marshals it to byte array
+// MarshalJSON capitalizes Error.Message and marshals it to byte array.
 func (e Error) MarshalJSON() ([]byte, error) {
 	if e.Message != nil && *e.Message != "" {
 		r := []rune(*e.Message)