Not sure if I explained my problem clearly
The code all works if I replace local_server String with text "mylocal.com" within the Blynk.config function call, it only breaks (or compile error as shown) if I actually use the String local_server in the function call as per screen shot. I can't work out why Blyn.config or Blynk.begin won't take a string ?
For example below will not compile:
/* Comment this out to disable prints and save space */
#define BLYNK_PRINT Serial
// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth = "YourAuthToken";
// Your WiFi credentials.
// Set password to "" for open networks.
char ssid = "YourNetworkName";
char pass = "YourPassword";
String cloud_server = "blynk-cloud.com";
// Debug console
// Blynk.begin(auth, ssid, pass);
// You can also specify server:
// Blynk.begin(auth, ssid, pass, "blynk-cloud.com", 8442);
Blynk.begin(auth, ssid, pass, cloud_server, 8442);
//Blynk.begin(auth, ssid, pass, IPAddress(192,168,1,100), 8442);
// You can inject your own code or combine it with other sketches.
// Check other examples on how to communicate with Blynk. Remember
// to avoid delay() function!
Throws the following compiler error: