I got the error! Please support me to setup! Thank you

Your message did not reach some or all of the intended recipients.

Sent: Thu, 02 Nov 2023 03:49:38 +0000
Subject: Thông báo tuyển dụng 2023 1

The following recipient(s) could not be reached:

thang.dominh1601@gmail.com
Error Type: SMTP
Remote server (64.233.167.27) issued an error.
hMailServer sent: .
Remote server replied: 550-5.7.26 This mail has been blocked because the sender is unauthenticated.
550-5.7.26 Gmail requires all senders to authenticate with either SPF or DKIM.
550-5.7.26
550-5.7.26 Authentication results:
550-5.7.26 DKIM = did not pass
550-5.7.26 SPF [nhasachapollo.online] with ip: [162.216.242.75] = did not pass
550-5.7.26
550-5.7.26 To mitigate this issue, please visit Gmail's authentication guide
550-5.7.26 for instructions on setting up authentication:
550 5.7.26 https://support.google.com/mail/answer/81126#authentication iv16-20020a05600c549000b004075a8cfc20si892249wmb.221 - gsmtp

This issue can be resolved by setting up a simple SPF record. The record is provided to you in the control panel email service settings. You may also choose to set up DKIM. However, if you are unsure how to set up DKIM, you can leave it not set up. Setting up a SPF record is sufficient to resolve this issue. For more details, you can refer to https://www.dynu.com/Resources/Tutorials/EmailServices/EmailServiceSetup/FullServiceEmail#SPFRecord. You can also open a support ticket and the support staff can assist you with all this.