@Madhu Rajawat FYI this issue only in the chrome browser, Firefox shows my success page.
Yes, Then for sure it is due to samesite attribute issue. samesite none is the feature of Chrome 80 feature. It restrict third party get and post data. If No value set for samesite then it set lax By Default and restrict get and Post Data.
Somewhere you still missing or not set properly samesite none. you can check in Application tab with Inspect Element.
With the adding code in Cookie.php Set Value frontend_cid Samesite none
You need to check for others cookie and set same as frontend_cid
@Madhu Rajawat Where i can set frontend_cid Samesite none?
@Aveeva frontend_cid Samesite none is already set if you see the screenshot.
You need to set for others cookie same as it set.
You can add same as given my solution but need to find out the cookie and proper file there you need to amend the code as per your website.
@Madhu Rajawat Could you pls help me to find those file, May i know what file you want to look, i will share?
I can suggest to you what you can do. you need to find out the cookie there you need to set.
Find with the keyword On all over your website file code
Also, find such as keyword _gid cookie name
I have already given you a solution that how you have to apply.
@Aveeva You can check by amend the code in these files too.