Hi @Shali_123
Have you tried to remove the proxy settings in Internet Explorer? You can remove the proxy setting by the following steps:
Open Internet Explorer > Internet Options > Connections > LAN settings > Proxy server > Select “Use a proxy server for your LAN (These settings will not apply to dial-up or VPN connections)” > Advanced
Please check your content access account have the right permissions.
References:
https://social.technet.microsoft.com/Forums/en-US/dfc8f206-1512-4032-8276-c0a7c4015766/sharepoint-content-source-crawling-error-quotan-unrecognized-http-response-was-received-when?forum=sharepointsearch
http://expertsharepoint.blogspot.com/2014/05/access-is-denied-verify-that-either.html
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