Lana Fraidenberguer

Hello,
I am having difficulties with email sending function from Volunteer Signup Sheet plug-in. The plug-in documentation was consulted and the following recommendations applied:
Using WP SMTP SendGrip mail client,
Separate CC/BCC to individual TO emails setting is checked “yes”
Test emails from SendGrid goes with no issues.

The support forum research gives exactly the same recommendations.

The error message from Volunteer Sign up plug in is “EMAIL DELIVERY ERROR: the plugin WP Mail SMTP v2.5.1 logged this error during the last time it tried to send an email:
Mailer: SendGrid
Header can not be one of the reserved keys. Refer to documentation link. – headers.Content-Transfer-Encoding; http://sendgrid.com/docs/API_Reference/Web_API_v3/Mail/errors.html#message.headers”

Would you be able to provide any further guidance or recommendation on how to fix this issue?
Thank you!