diff --git a/Dockerfile b/Dockerfile
index 0be2ff5..0ae34c8 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -4,8 +4,8 @@ WORKDIR /app
 COPY ./package.json ./
 RUN npm install
 COPY ./ ./
-ENV PUBLIC_API_URL=https://publitebackend.dm1sh.ru
-ENV PUBLIC_BASE_URL=https://publite.dm1sh.ru
+ARG PUBLIC_API_URL=https://publitebackend.dm1sh.ru
+ARG PUBLIC_BASE_URL=https://publite.dm1sh.ru
 RUN NODE_ENV=production npm run build
 
 FROM node:alpine
diff --git a/README.md b/README.md
index ded6ca8..c82b09d 100644
--- a/README.md
+++ b/README.md
@@ -41,10 +41,10 @@ Simple docker deployment
 
 ```bash
 # build docker image
-docker build . -t publite_frontend
+docker build . --build-arg PUBLIC_API_URL=<> --build-arg PUBLIC_BASE_URL=<> -t publite_frontend
 
 # run it with docker
-docker run -p <port>:80 publite_frontend
+docker run -p <port>:8080 publite_frontend
 ```
 
 Dokku deployment with image from Docker Hub
diff --git a/src/utils/api.ts b/src/utils/api.ts
index 4ea53a8..3810ae1 100644
--- a/src/utils/api.ts
+++ b/src/utils/api.ts
@@ -5,6 +5,11 @@ import { API_URL } from "~/constants";
 export const validState = (file: File | undefined): file is File => {
   if (!file) throw new Error("Book file is required. Please, attach one");
 
+  if (file.name.endsWith(".zip"))
+    throw new Error(
+      "Please, unzip file before sending to reader if it is fb2.zip"
+    )
+
   if (!file.name.match(/\.(fb2|epub)/))
     throw new Error(
       "Wrong file type. Only FB2 and Epub files are supported. \