Don't try zeroing an object (it's not a pointer...)

PositionGaugeServer.ino

@@ -623,12 +623,11 @@ void TXTserver (uint8_t ch) {
   for (byte i = 0; i < MAX_SOCK_NUM; i++) { 
     if ( clients[i] && (clients_ch[i]==ch) && !clients[i].connected() ) {
       clients[i].stop();
-      clients_ch[i]=0;
 
-        Serial.print("Closed connection for ch=");
-        Serial.print(ch);
-        Serial.print(" slot ");
-        Serial.println(i);
+      Serial.print("Closed connection for ch=");
+      Serial.print(ch);
+      Serial.print(" slot ");
+      Serial.println(i);
     }
   }
 }