# Email error with Mimecast: 501 - Invalid Email Address

**URL:** <https://community.synatic.com/t/email-error-with-mimecast-501-invalid-email-address/115>\
**Category:** Flows\
**Tags:** email, error-501\
**Created:** [May 28, 2021, 1:09pm UTC](https://community.synatic.com/t/email-error-with-mimecast-501-invalid-email-address/115 "2021-05-28T13:09:29Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![shaun](https://yyz2.discourse-cdn.com/flex032/user_avatar/community.synatic.com/shaun/32/7_2.png) [@shaun](https://community.synatic.com/u/shaun)\
**Post date:** [May 28, 2021, 1:09pm UTC](https://community.synatic.com/t/email-error-with-mimecast-501-invalid-email-address/115/1 "2021-05-28T13:09:29Z")

</div>

Mimecast can block an email delivery with the following error:

_Error 501: Invalid Email Address._

This implies that either the email address does not exist, or, the structure of the email address contains characters that cannot be used within an email address.

If you make use of distribution list in Synatic, its important to check that you don’t have any spaces (" ") preceding the email address.

E.g. **test1@test.test; test2@test.test** vs **test1@test.test;test2@test.test**

Noting the spacing between the two email addresses. Removing this space should resolve this issue.