Return tag error (page does not link back) Language-region code has no standalone language code
The error should be more of a warning and just means that for
af-ZA you did not define a link for
af, the "standalone" language code associated to your region-scoped language-region code
The tool complains about this, but not Google.
But if you want to suppress that problem, just use
af instead of
af-ZA (do you really have different translations for Afrikaans in South Africa vs Afrikaans anywhere else? If not,
af is good enough, because if you use
af-ZA it gives the semantics that you are using the Afrikaans language as spoken in South Africa vs how it is spoken in other countries, so you are kind of "excluding" other people speaking Afrikaans but from other countries than South Africa)
Note that testing your website right now yields the exact same problem for
tr-TR, for the exact same resolution. Do you really want to target Turkish as a language only as spoken in Turkey (vs other parts of the world where it can be spoken), or you just mean the language anywhere (in which case, use
tr as language tag)?
This is kind of explained, in German at https://blog.bloofusion.de/drei-wichtige-tools-um-hreflang-fehler-zu-finden/. It also mentions another online checker: http://flang.dejanseo.com.au/ which does not detect problems with your site.