So, I have a niche blog started in June 2017. After the first year (with around one day before the expiration date), I have changed the domain, because the old one wasn't related to the niche. But, I didn't renew the first domain to make 301 redirects to the second one, because of the cost.
The problem is that now, the old articles don't show in the first page on Google anymore. I knew that this is going to happen if I don't renew the old domain, but I thought that three months are enough for them to recover their SEO rankings... Meanwhile, the articles written after the domain change started to show up in the first pages.
My question is: Do you think that this can be considered duplicate content? If not, how long should I wait until the old articles will show up again in the first search pages? Thanks!