If you are facing this "Solved : Alternate page with proper canonical tag Simple Solution" error then you just need to you it's happened. Firstly you should know that it's not a big error or affect your site.
Solution -
I'm my case I'm working on books so mostly books publication is "NIMI" more then 20% post tagged with
"NIMI Books" and "ITI NIMI Books"
so Google detected that the both tags are same. In google search console, it create "Alternate page with proper canonical tag" error
To remove this error, you have to remove any one tag or add one more 3rd tag, any relevant tag you can add then Copy past post link and request for Indexing. You can see the error has been removed.
