Performance issue while sending request for the first time

My application works very slow for the first time. Example. I open login page. Fills credential. Submits page. This will come back after 44 seconds. **Below is Live Url.** > Url: [login to view URL] Request Type: Post **When I test it in Postman App in Chrome or in Fiddler. It takes 40 seconds min for the first time.** Then I do logout and tries login again...this time I can enter in the site in 1 second. I tested this behavior and this is happening every time. Here another problem is that when new user tries to login..they face same issue. Problem also persist when I try to login after an hour. Same amount of time is being taken. Kindly suggest what can be the root cause.