Hi @Nadhrah Nini ,
What format of SPF record do you set?
According to the MXToolBox article, the cause of the warning is "The use of alternative DNS RR types that was formerly supported during the experimental phase of SPF was discontinued in 2014. SPF records must now only be published as a DNS TXT (type 16) Resource Record (RR) [RFC1035].". So please check and make sure that the format of the SPF record you set is TXT.
For more information please refer to: SPF Record Deprecated
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