I'm trying to resolve the site crawl issues that we have on our website. One of the links that has different issue types together is our login page. Currently we have two login pages that have the same content but different sub domains. **However I'm wondering if optimizing SEO on our login pages affects our website SEO ranking and if it's something better to do or not. **

To point out the details of the issues, the issue types that the logins pages have are "duplicate title", "duplicate content", "missing H1", "missing description", "thin content", "missing canonical tag"

I'd appreciate your help, thank you!