How to add return to previous URL after log in based on a link rather than redirect

I've got content on a page that I am hiding from users when they are not logged in. I have a button on the page for them to log in with, and I want them to return to the article they were looking at so it's easy for them to read rather than have to find it again. I've had a look through previous posts about this, and have copied a link to my page to pass the query like so:

<a href="login.php?accesscheck=<?php echo (urlencode($_SERVER["PHP_SELF"].(isset($_SERVER["QUERY_STRING"])?"?".htmlentities($_SERVER["QUERY_STRING"]):"")));?>">Log In</a>

It just takes me straight to the user account.php rather than back to the original posting page. Here's the log in page code:

<?php
if($_SERVER["REQUEST_METHOD"] == "POST"){
$WA_Auth_Parameter = array(
"connection" => $conn_mrs,
"database" => $database_conn_mrs,
"tableName" => "tbl_users",
"columns" => explode($WA_Auth_Separator,"UserEmail".$WA_Auth_Separator."UserPassword"),
"columnValues" => explode($WA_Auth_Separator,"".((isset($_POST["Log_In_group_Email"]))?$_POST["Log_In_group_Email"]:"") ."".$WA_Auth_Separator."".(WA_SHA1Encryption((isset($_POST["Log_In_group_Password"]))?$_POST["Log_In_group_Password"]:"")) .""),
"columnTypes" => explode($WA_Auth_Separator,"text".$WA_Auth_Separator."text"),
"sessionColumns" => explode($WA_Auth_Separator,"UserID".$WA_Auth_Separator."emailVerified"),
"sessionNames" => explode($WA_Auth_Separator,"SecurityAssist_UserID".$WA_Auth_Separator."emailVerified"),
"successRedirect" => "useraccount.php",
"failRedirect" => "login.php?failedLogin=1",
"gotoPreviousURL" => TRUE,
"keepQueryString" => TRUE
);

WA_AuthenticateUser($WA_Auth_Parameter);
}
?>
<?php
if((((isset($_SESSION["SecurityAssist_UserID"]) && $_SESSION["SecurityAssist_UserID"] != "")?"LoggedIn":"") == "")&&(((isset($_COOKIE["AutoLoginUN"]))?$_COOKIE["AutoLoginUN"]:"") != "")&&(((isset($_COOKIE["AutoLoginPWD"]))?$_COOKIE["AutoLoginPWD"]:"") != "")){
$WA_Auth_Parameter = array(
"connection" => $conn_mrs,
"database" => $database_conn_mrs,
"tableName" => "tbl_users",
"columns" => explode($WA_Auth_Separator,"UserEmail".$WA_Auth_Separator."UserPassword"),
"columnValues" => explode($WA_Auth_Separator,"".((isset($_COOKIE["AutoLoginUN"]))?$_COOKIE["AutoLoginUN"]:"") ."".$WA_Auth_Separator."".(WA_SHA1Encryption((isset($_COOKIE["AutoLoginPWD"]))?$_COOKIE["AutoLoginPWD"]:"")) .""),
"columnTypes" => explode($WA_Auth_Separator,"text".$WA_Auth_Separator."text"),
"sessionColumns" => explode($WA_Auth_Separator,"UserID".$WA_Auth_Separator."emailVerified"),
"sessionNames" => explode($WA_Auth_Separator,"SecurityAssist_UserID".$WA_Auth_Separator."emailVerified"),
"successRedirect" => "",
"failRedirect" => "",
"gotoPreviousURL" => TRUE,
"keepQueryString" => TRUE
);

WA_AuthenticateUser($WA_Auth_Parameter);
}
?>

What am I missing?

Thanks.

I'll need to troubleshoot directly, see the private message section.

Sorry for the delay in responding. Had a meeting. See below and files attached.

If I use the link 'Log in' to check access and pass the URL, then the got to previous URL doesn't work, but if I try to access a page that is protected, then I get redirected to login.php and then back to the initial URL as expected. I've obviously missed something minor in my login link I think, but don't know what.

Thank you.

PS... just a thought, in the detail page I've attached, do I need to reference the security assist helper?

on the login page, i changed the action of the form to:
action="<?php echo(htmlentities($_SERVER["PHP_SELF"], ENT_QUOTES)."?".$_SERVER["QUERY_STRING"]); ?>"


this corrected the problem.