Hi Thorsten, this has also been a frustration for me for years and I’ve been through all of the threads on other sites about this several times…. but I’ve finally found a solution, if it helps you:
In Post SMTP’s Settings, under the Message tab (from address section):
Fill in the fields ad tick “Prevent plugins and themes from changing this” for BOTH the email address and name (just ticking the name tickbox doesn’t make any difference).
This removes the quotes/apostrophes from the FROM header when emails are sent. I’ve tested this on various sites and also with various Gravity Forms notification emails. I don’t know if it works with other plugins so anyone else has any info, do shout.
All the best!
Shaun
Craven Digital, UK
