It looks like the string you provided — "Download- tjmyt nwdz lbt sghyrt wtkt tql wtqfsh..." — is not in plain English. It appears to be encoded, possibly with a simple substitution cipher like or an Atbash cipher .
Let’s check "nwdz": n(14)-5=9=i, w(23)-5=18=r, d(4)-5=-1+26=25=z, z(26)-5=21=v → "irzv" — not common.
However, based on the phrase "Download- ..." possibly the decoded text is something like: