Error response in Aadhaar Authentication API for version 2.5 C#

Question

I am implementing project in c# for validating user Aadhaar number. Using API and license keys are as given in the URL for testing purposes.

Auth XML format seems correct, Authentication API is returning response status code 510 "Invalid AUTH XML"

License and certificate file downloaded from : https://www.uidai.gov.in/en/ecosystem/authentication-devices-documents/developer-section/916-developer-section/data-and-downloads-section.html

Following is the request XML generated:

<Auth tid="" ac="public" sa="public" txn="20230519031016736" lk="MAElpSz56NccNf11_wSM_RrXwa7n8_CaoWRrjYYWouA1r8IoJjuaGYg" uid="999941057058" ver="2.5" rc="Y">
  <Uses pi="y" pa="n" pfa="n" bio="n" pin="n" otp="n" />
  <Device dc="ABCDE.20150101.00001" />
  <Skey ci="20250825">pt5kh3zKxoC56g8Uqvc1ASM3dwdzLsziubFpO1sYki0/SlGfo4wSOXgNbWCaOWlsA2X5WW3orpvAyvEABVVizuqQw7+477xnPNUFwwIG1BhqFmyt+mPWKEhBzWVcdCv2/rBjBVn5BkR3oS1+9WNSxMMwmXifGksf+bUJ4r7c+3YlLLlxGUfUe/H8niOT5YuhTbqPOk1vl7nbapXR/4W+/J66yKvZEdH//d5pvTXPnZiEzkCq7gxDubQCuMLj8JPuG54pAgPEQcCXexVt1Po1A4KwnkZckHSLdEPQW4XPGNRERzpvZH8WAIk2xLK+yvvowhNUTn7ohnLGHto8+m4K4Q==</Skey>
  <Hmac>Go0l0As1iUmPYm4JMfJQ9/NSHYBm4GTFo1kKcb2NcNaOuwxVpIHnpTuSrsqYwGZq</Hmac>
  <Data>xSRU89jmnzE8dAJVhyPYjN+fLRw7UDhfEv608GuTcwGbxPkq5G/aYhfko6+JYZhCGus71/IRKCG+1fKfgmg4tcYxVWbBUSltBtpx/43zTUL4u9tP5oF9NqsyVtTg37XjbekRtN5OKssf3radLAB5599R2zKh/4r7PaeiWguYHgz49epg1OymPLOGRBZBrurSBXPdR/v72+dsCGxaO3748nMh8eWcQccpvp+uxro4YYG2JpnFfV2Y/6Lk7NFPpS03</Data>
  <Signature W9QPVw+JLHabGlRNe3C4xMZ1rdCUslQ7VshQlkDQIxiu9jOk+B1wexT78wtVGvunolkCAwEAAaMhMB8wHQYDVR0OBBYEFB6nQeWTHs78YZvfDfnSWIuXuU2cMA0GCSqGSIb3DQEBBQUAA4IBAQAp+MnpqVO1SJ+ilCS++L7WV4AQlVTwCzHW4QyIV+6Mb50PIYhmoFXjKF7t71jvQ3WP2jocp7Ouy07+sT7Knuhy4/RpCwCSyZpKCQjfRqKPEW8CYc17TEYUxufvwBfzzOGZCTIwtgGrOC23XoVXNd+bwn1Lbsrb0dd98Rp3AGccwcVPp8TgwzNY2oH78HRF/ScUONebyCT+eOICVxjc73qnYvGe5t25bl/kgm6NsAYimr/at7suqiMZQWp5SEfbRYCZ9wvQsJgX01g92zk3ELV9g5fbO9VrKr9vN0QA7VjkrfzuCtR/MGIsYBpZzcX1vDlUscXO1u4fVROETTOSS3jc</X509Certificate>
      </X509Data>

    </KeyInfo>
  </Signature>
</Auth>

Response is following :

<AuthRes code="NA" err="510" info="04{010000689q0UyziZPIvP9psR7eeHCLTGQuscB3As0GtBvc3Y9BpSDLUyPHUEpdBbazemTkw7,A,00000000000000000000000000000000000000000000000000000000000000000000000,0100000000000000,NA,NA,NA,NA,NA,NA,2.5,20ef0f0c8d0eea98772412cea9b3b92612e3e53cb5e59152b5703165f56e8a53,efa1f375d76194fa51a3556a97e641e61685f914d446979da50a551a4333ffd7,NA,NA,NA,NA,NA,NA,NA,NA,NA,NA,NA,,NA,NA,NA,NA,NA,NA}" ret="n" ts="2023-05-19T15:11:43.579+05:30" txn="20230519031016736">
  <Signature >
  </Signature>
</AuthRes>

Please help/guide in understanding the issue.