Cannot use windows-1251 codepage.
1) Case stack trace:
The character set provided in ContentType is invalid. Cannot read content as string using an invalid character set.
at System.Net.Http.HttpContent.ReadBufferAsString(ArraySegment`1, HttpContentHeaders) + 0x17f
at System.Net.Http.HttpContent.ReadBufferedContentAsString() + 0xa5
...
Firefox RESTer succesfully return
content-type: application/json; charset=windows-1251
content-length: 103
2) Case https://pda.nakanune.ru return
Cannot use windows-1251 codepage. 1) Case stack trace: The character set provided in ContentType is invalid. Cannot read content as string using an invalid character set. at System.Net.Http.HttpContent.ReadBufferAsString(ArraySegment`1, HttpContentHeaders) + 0x17f at System.Net.Http.HttpContent.ReadBufferedContentAsString() + 0xa5 ... Firefox RESTer succesfully return content-type: application/json; charset=windows-1251 content-length: 103 2) Case https://pda.nakanune.ru return