I use a third party email called fastmail for my office email and personale email. On the whole its work out cheaper than google an godaddy. When I was with wix i had no problem with this issue. I would add my SPF records, MX and DKIM record without any problem but with squarespace it seems like there is issues with SPF records. See attachment. it seems pretty straight forward but fastmail does not seem to see this entry from squarespace. I bought my domain through squarespace. I need some help on this matter.