Delete space after equal sign action= "<?php echo $current_page; ?>"
replace to action="<?php echo $current_page; ?>"
and never use equal sign for compare username and password in the MySQL! Try this test case:
SELECT 'ABC' = 'abc','ĀBČ' = 'abc','ābč' = 'abc', 'ABC' LIKE 'abc',
'ĀBČ' LIKE 'abc', 'ābč' LIKE 'abc', 'ABC' LIKE BINARY 'abc',
'ĀBČ' LIKE BINARY 'abc', 'ābč' LIKE BINARY 'abc';
only "LIKE BINARY" return FALSE any other return TRUE (MySQL)