diff --git a/functions/src/config/firebase.ts b/functions/src/config/firebase.ts
index c4b779a..3220171 100644
--- a/functions/src/config/firebase.ts
+++ b/functions/src/config/firebase.ts
@@ -11,6 +11,7 @@ admin.initializeApp({
 });
 
 const db = admin.firestore();
+db.settings({ ignoreUndefinedProperties: true });
 const auth = admin.auth();
 
 /**
diff --git a/functions/src/controllers/application_controller.ts b/functions/src/controllers/application_controller.ts
index da9d151..4c27663 100644
--- a/functions/src/controllers/application_controller.ts
+++ b/functions/src/controllers/application_controller.ts
@@ -162,7 +162,8 @@ async function constructDataToSave(
   for (const question of questions) {
     if (question.id === undefined || question.id === null) continue;
     const fieldValue = req.body[question.id];
-    if (question.type === QUESTION_TYPE.FILE) {
+    // rewrite file path
+    if (question.type === QUESTION_TYPE.FILE && !(fieldValue === undefined || fieldValue === "" || fieldValue === null)) {
       dataToSave[
         question.id
       ] = `${STORAGE_BASE_LINK}${USER_UPLOAD_PATH}${UID}_${
@@ -274,10 +275,19 @@ async function validateFileUploaded(
   question: Question,
   uid: string
 ) {
-  const errors = [];
+  const errors: { field_id: string; message: string; }[] = [];
 
   const validation = question.validation as FileValidation;
 
+
+  // skip validation if not required and value is empty
+  if (
+    validation.required !== true &&
+    (fieldValue === undefined || fieldValue === "" || fieldValue === null)
+  ) {
+    return errors;
+  }
+
   // required
   if (
     validation.required === true &&
@@ -324,10 +334,18 @@ async function validateFileUploaded(
 
 // eslint-disable-next-line require-jsdoc
 function validateDropdownValue(fieldValue: string | any, question: Question) {
-  const errors = [];
+  const errors: { field_id: string; message: string; }[] = [];
 
   const validation = question.validation as DropdownValidation;
 
+  // skip validation if not required and value is empty
+  if (
+    validation.required !== true &&
+    (fieldValue === undefined || fieldValue === "" || fieldValue === null)
+  ) {
+    return errors;
+  }
+
   // required
   if (
     validation.required === true &&
@@ -353,10 +371,18 @@ function validateDropdownValue(fieldValue: string | any, question: Question) {
 
 // eslint-disable-next-line require-jsdoc
 function validateDatetimeValue(fieldValue: string, question: Question) {
-  const errors = [];
+  const errors: { field_id: string; message: string; }[] = [];
 
   const validation = question.validation as DatetimeValidation;
 
+  // skip validation if not required and value is empty
+  if (
+    validation.required !== true &&
+    (fieldValue === undefined || fieldValue === "" || fieldValue === null)
+  ) {
+    return errors;
+  }
+
   // required
   if (
     validation.required === true &&
@@ -381,10 +407,18 @@ function validateDatetimeValue(fieldValue: string, question: Question) {
 
 // eslint-disable-next-line require-jsdoc
 function validateNumberValue(fieldValue: number | any, question: Question) {
-  const errors = [];
+  const errors: { field_id: string; message: string; }[] = [];
 
   const validation = question.validation as NumberValidation;
 
+  // skip validation if not required and value is empty
+  if (
+    validation.required !== true &&
+    (fieldValue === undefined || fieldValue === "" || fieldValue === null)
+  ) {
+    return errors;
+  }
+
   // required
   if (
     validation.required === true &&
@@ -410,14 +444,16 @@ function validateNumberValue(fieldValue: number | any, question: Question) {
   if (validation.minValue && fieldValue < validation.minValue) {
     errors.push({
       field_id: `${question.id}`,
-      message: `Must be more than equals ${validation.minValue}`,
+      message: `Must be more than or equal to ${validation.minValue}`,
     });
-  } else if (validation.maxValue && fieldValue > validation.maxValue) {
+  }
+  if (validation.maxValue && fieldValue > validation.maxValue) {
     errors.push({
       field_id: `${question.id}`,
-      message: `Must be less than equals ${validation.maxValue}`,
+      message: `Must be less than or equal to ${validation.maxValue}`,
     });
   }
+
   return errors;
 }
 
@@ -425,10 +461,18 @@ function validateNumberValue(fieldValue: number | any, question: Question) {
  * Validate string value. Also works for textarea.
  */
 function validateStringValue(fieldValue: string | any, question: Question) {
-  const errors = [];
+  const errors: { field_id: string; message: string; }[] = [];
 
   const validation = question.validation as StringValidation;
 
+  // skip validation if not required and value is empty
+  if (
+    validation.required !== true &&
+    (fieldValue === undefined || fieldValue === "" || fieldValue === null)
+  ) {
+    return errors;
+  }
+
   // required
   if (
     validation.required === true &&
diff --git a/functions/src/controllers/auth_controller.ts b/functions/src/controllers/auth_controller.ts
index 8ba6210..dfa2a55 100644
--- a/functions/src/controllers/auth_controller.ts
+++ b/functions/src/controllers/auth_controller.ts
@@ -282,7 +282,7 @@ export const sessionLogin = async (
       user = await auth.getUserByEmail(decodedIdToken.email);
 
       // update user record for first time
-      const docRef = await db.collection("questions").doc(user.uid).get();
+      const docRef = await db.collection("users").doc(user.uid).get();
       if (!docRef.exists) {
         const userData: User = formatUser({
           email: user.email ?? "",