Email notifications come with plain text like this:
=_swift_v4_1678471918_a180a6e88ef1552cb292f33d9665c713=_ Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Usually, this issue is related to a bad configuration of the PHP mail() function. To fix it, we suggest using an SMTP account or another alternative we offer, like Sendinblue, Sendgrid or Amazon SES.
So, just go to Mail Settings, select SMTP, and use your SMTP account.
Doc. | Configure Access To Your SMTP Account
Just in case, we have tested it and we can’t reproduce this issue in our servers.