Cannot use old slug – it just 301s to site home page

I had the same problem a few weeks ago, this is what solved it for me:

Went to Settings / Permalinks, switched to Plain and Saved.
After that I changed Permalink settings back to the previously used values and it worked.

Let me know if this fixes your issues.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)