ERPNext Email Delivery Service: This email was blocked as it was flagged as spam.

Hi All,

I am getting this error when I try to send welcome email or any email via ERPNext Email Delivery Service

This email was blocked as it was flagged as spam. Please review documentation corresponding to the error codes below: docs: SpamAssassin: Tests Performed: v3.3.x SPAMD/1.1 0 EX_OK Content-length: 164 Spam: False ; 4.2 / 5.0 DKIM_ADSP_CUSTOM_MED,FORGED_GMAIL_RCVD,FREEMAIL_FROM,HK_RANDOM_FROM,HK_RANDOM_REPLYTO,HTML_MESSAGE,NML_ADSP_CUSTOM_MED,NO_RECEIVED,NO_RELAYS,T_KAM_HTML_FONT_INVALID

Please do share any steps that I might have missed to configure Email Delivery Service.

Anyone can help me?