"No return tags " - webmaster tools - International targeting

[Sam.c]

I am recently having an increased number of "hreflang no return tags" error on the Google webmaster console and I cannot figure ou what I am missing.

My site, www.example.com, is a SAP (AngularJS) and it can be accessed in different languages as www.example.com/#!/xx, where xx is one of the following options: it, ro, ru, pt, en, es.

For each language, I set the following hreflang urls and set the x-default url to en:

<link view-head rel="alternate" hreflang="x-default" href="{{domain_absolute}}#!/en/--about-us" />
<link view-head rel="alternate" hreflang="es" href="{{domain_absolute}}#!/es/--about-us" />
<link view-head rel="alternate" hreflang="pt" href="{{domain_absolute}}#!/pt/--about-us" />
<link view-head rel="alternate" hreflang="ro" href="{{domain_absolute}}#!/ro/--about-us" />
<link view-head rel="alternate" hreflang="ru" href="{{domain_absolute}}#!/ru/--about-us" />
<link view-head rel="alternate" hreflang="en" href="{{domain_absolute}}#!/en/--about-us" />
<link view-head rel="alternate" hreflang="it" href="{{domain_absolute}}#!/it/--about-us" />
<link view-head rel="alternate" hreflang="fr" href="{{domain_absolute}}#!/fr/--about-us" />


And the errors I get from Google are the following:

Original URL : #!/en/some-document
Alternate URLs: http://www.example.com/?_escaped_fragment_=/en and http://www.example.com/?_escaped_fragment_=/en/some-document - no return tags

I get the same errors for all of the supported languages.

What am I doing wrong? Is this has something to do with googlebot trying to access the pages with ?_escaped_fragment_= ?

Should the canonical url have the same structure as the alternate url?