diff --git a/api.go b/api.go
index 4eb7ea6..1fee741 100644
--- a/api.go
+++ b/api.go
@@ -2095,7 +2095,7 @@ func (app *appContext) GetConfig(gc *gin.Context) {
 // @Produce json
 // @Param appConfig body configDTO true "Config split into sections as in config.ini, all values as strings."
 // @Success 200 {object} boolResponse
-// @Failure 500 {object} boolResponse
+// @Failure 500 {object} stringResponse
 // @Router /config [post]
 // @Security Bearer
 // @tags Configuration
@@ -2126,7 +2126,7 @@ func (app *appContext) ModifyConfig(gc *gin.Context) {
 	tempConfig.Section("").Key("first_run").SetValue("false")
 	if err := tempConfig.SaveTo(app.configPath); err != nil {
 		app.err.Printf("Failed to save config to \"%s\": %v", app.configPath, err)
-		respondBool(500, false, gc)
+		respond(500, err.Error(), gc)
 		return
 	}
 	app.debug.Println("Config saved")
diff --git a/ts/setup.ts b/ts/setup.ts
index 5ecf84c..2a1a190 100644
--- a/ts/setup.ts
+++ b/ts/setup.ts
@@ -340,6 +340,20 @@ const serialize = () => {
     _post("/config", config, (req: XMLHttpRequest) => {
         if (req.readyState == 4) {
             toggleLoader(restartButton);
+            if (req.status == 500) {
+                if (req.response["error"] as string) {
+                    const old = restartButton.textContent;
+                    restartButton.classList.add("~critical");
+                    restartButton.classList.remove("~urge");
+                    restartButton.textContent = req.response["error"];
+                    setTimeout(() => {
+                        restartButton.classList.add("~urge");
+                        restartButton.classList.remove("~critical");
+                        restartButton.textContent = old;
+                    }, 5000);
+                    return;
+                }
+            }
             restartButton.parentElement.querySelector("span.back").classList.add("unfocused");
             restartButton.classList.add("unfocused");
             const refresh = document.getElementById("refresh") as HTMLSpanElement;