diff --git a/src/main/java/io/cryostat/ExceptionMappers.java b/src/main/java/io/cryostat/ExceptionMappers.java
index a1895beb1..f03dc89fd 100644
--- a/src/main/java/io/cryostat/ExceptionMappers.java
+++ b/src/main/java/io/cryostat/ExceptionMappers.java
@@ -48,4 +48,9 @@ public RestResponse<Void> mapScriptException(ScriptException ex) {
     public RestResponse<Void> mapNoSuchKeyException(NoSuchKeyException ex) {
         return RestResponse.status(HttpResponseStatus.NOT_FOUND.code());
     }
+
+    @ServerExceptionMapper
+    public RestResponse<Void> mapIllegalArgumentException(IllegalArgumentException exception) {
+        return RestResponse.status(HttpResponseStatus.BAD_REQUEST.code());
+    }
 }
diff --git a/src/test/java/itest/RulesPostJsonIT.java b/src/test/java/itest/RulesPostJsonIT.java
index 003777bda..838ff1f6b 100644
--- a/src/test/java/itest/RulesPostJsonIT.java
+++ b/src/test/java/itest/RulesPostJsonIT.java
@@ -37,7 +37,6 @@
 import org.junit.jupiter.api.Order;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.TestMethodOrder;
-import org.junit.jupiter.api.condition.DisabledIfEnvironmentVariable;
 
 @QuarkusIntegrationTest
 @TestMethodOrder(OrderAnnotation.class)
@@ -107,12 +106,6 @@ void testAddRuleThrowsWhenMimeUnsupported() throws Exception {
                 ex.getCause().getMessage(), Matchers.equalTo("Unsupported Media Type"));
     }
 
-    @DisabledIfEnvironmentVariable(
-            named = "CI",
-            matches = "true",
-            disabledReason =
-                    "The server 500 seems to cause issues for the next test in the suite, ex. HTTP"
-                            + " connection closed when attempting to POST the next rule definition")
     @Test
     @Order(3)
     void testAddRuleThrowsWhenMimeInvalid() throws Exception {
@@ -131,9 +124,8 @@ void testAddRuleThrowsWhenMimeInvalid() throws Exception {
                 Assertions.assertThrows(
                         ExecutionException.class, () -> response.get(10, TimeUnit.SECONDS));
         MatcherAssert.assertThat(
-                ((HttpException) ex.getCause()).getStatusCode(), Matchers.equalTo(500));
-        MatcherAssert.assertThat(
-                ex.getCause().getMessage(), Matchers.equalTo("Internal Server Error"));
+                ((HttpException) ex.getCause()).getStatusCode(), Matchers.equalTo(400));
+        MatcherAssert.assertThat(ex.getCause().getMessage(), Matchers.equalTo("Bad Request"));
     }
 
     @Test