Help:Crawling but Not Indexing after Migrating Domain & Hosting?

I rebranded one of my blogs 2 months ago, buy new domain and migrate the content to a new hosting account. I've built back links but Google is only indexing One page in 2 or 3 days and I still have hundreds of pages to be indexed right now. How can I index those pages quickly? I also need help with SEO-rich robot.txt template.

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