Physical KeyBoard Not working For TextFormField in desktop Flutter

Recently I started making an admin panel on a desktop and using a text form field to take input from the user but unfortunately, the keyboard cannot write data inside the text field, I searched on Google and did not find any solution, please can someone help me?

Here is some of the text fields that I am using in my project:

Container(
                            width: 200,
                            margin: EdgeInsets.all(15),
                            child: TextFormField(
                              onChanged: (value) {
                                referalName.text = value;
                              },
                              validator: (value) {
                                if (value!.isEmpty) {
                                  return 'Please Enter Referal Code';
                                }
                                return null;
                              },
                              controller: referalName,
                              style: TextStyle(
                                fontSize: 24,
                                color: Colors.blue,
                                fontWeight: FontWeight.w600,
                              ),
                              decoration: InputDecoration(
                                focusColor: Colors.white,
                                //add prefix icon
                                prefixIcon: Icon(
                                  Icons.person_outline_rounded,
                                  color: Colors.grey,
                                ),

                                border: OutlineInputBorder(
                                  borderRadius: BorderRadius.circular(10.0),
                                ),

                                focusedBorder: OutlineInputBorder(
                                  borderSide: const BorderSide(
                                      color: Colors.blue, width: 1.0),
                                  borderRadius: BorderRadius.circular(10.0),
                                ),
                                fillColor: Colors.grey,

                                hintText: "Referal Name",

                                //make hint text
                                hintStyle: TextStyle(
                                  color: Colors.grey,
                                  fontSize: 16,
                                  fontFamily: "verdana_regular",
                                  fontWeight: FontWeight.w400,
                                ),

                                //create lable
                                labelText: 'Enter Referal Name',
                                //lable style
                                labelStyle: TextStyle(
                                  color: Colors.grey,
                                  fontSize: 16,
                                  fontFamily: "verdana_regular",
                                  fontWeight: FontWeight.w400,
                                ),
                              ),
                            ),
                          ),