Hi @HakeshDigital
Does it work if you remove, or comment out, the indicated line from your .htaccess file...
RewriteCond %{REQUEST_URI} ^(.*)/([a-z]{2})$
RewriteRule ^(.*/)(es|en|it|pt)$ $1$2/ [R=301,L]
RewriteRule ^(.*/)es$ ^(.*/)es/ [R=301] ## <<< Remove this line, or comment out with # at the start.
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule (.+(?:es|en|it|pt))$ /$1/ [L,R=301]
RewriteCond %{REQUEST_URI} ^/([a-z]{2})/
RewriteRule ^ - [E=LANG:%1]
RewriteCond %{ENV:LANG} !^$
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_URI} !(.*)/$
RewriteRule ^(.*)$ /$1/ [L,R=301]
...?