When my website sends emails to set or reset the password, they sometimes don't arrive at the recipient.

This problem does not arise for email addresses at large providers (as Google or Microsoft), but often email servers of schools or state institutions.

I guess that this is due to some bad spam filtering, where the email is just deleted without any notice to the recipient.

What I tried so far to reduce the problem:

• use a real email account, not something like sendmail
• start the email with "Hello X Y", where X Y is the real given name and surname of the addressed person.

But this had not the desired effect.