I'm having issues during alias creation.
Ensure you've followed these steps: https://improvmx.com/guides/send-emails-using-gmail/ to a tee.
Double check the SMTP server you're using to authenticate — it should be
You'll need to utilize your Gmail account email + an app password created within your Google account settings to authenticate — not your standard Gmail password. Refer to steps 1 and 2 here: https://improvmx.com/guides/send-emails-using-gmail/
Try refreshing the page, using an alternative browser (or incognito/private mode), and/or clear cache + cookies for your session.
Mail is landing in spam or has a warning message.
Ensure that you have unticked the "treat as alias" box within the alias creation process — step 4 of https://improvmx.com/guides/send-emails-using-gmail/
Are you replying to your alias from within an email thread while sending from the same Gmail account that you're forwarding to? I.E. I receive an email and/or reply from email@example.com, I click reply, and send to firstname.lastname@example.org from my Gmail account (the same one I'm forwarding to). Gmail detects a loop with this behavior, and the issue is similar to https://improvmx.com/guides/testing-forwarding-same-gmail-account/
Have you set an SPF record for your domain, and has it propagated? The SPF/TXT record can be seen in step 4 here: https://improvmx.com/guides/configure-your-dns/
*You can check to see if DNS has propagated for your domain utilizing tools like check.mx and mxtoolbox.com.
Nothing happens when I hit the send button.
If you're sending an email to your alias from within the same Gmail account that you are forwarding to, Google will detect a loop and drop the message. The email will only appear in the sent mailbox. All other senders and receivers should work just fine. https://improvmx.com/guides/testing-forwarding-same-gmail-account/
Occasionally, your browser will need a refresh and/or session clear after creating the alias. Try again from an alternative browser and/or after clearing cache + cookies for the current session.
Via Gmail/Via ImprovMX note
An alternative to Gmail SMTP which does not display the "via" note is ImprovMX SMTP. This feature is available to all premium and business-tier users: http://help.improvmx.com/en/articles/4633032-how-to-use-improvmx-smtp-with-gmail
The "via" note is automatically added to messages sent via Gmail SMTP. It's not possible for ImprovMX to alter the behavior or occurrence of the "via" note, as this occurs within Google's infrastructure.
If sending from your alias displays "via ImprovMX", it is setup incorrectly. Please ensure that your alias is not "treated as an alias" as per step 4 here.
Nothing worked, I still have issues or questions.
Please keep in mind that this "send mail as..." feature utilizing Gmail SMTP is undocumented and a relic of an old function Google provided. At some point, Google could disable this functionality. Since this is out of our control, we are unable to fully troubleshoot support requests of this type.
To counter this, we now offer a custom SMTP solution with our premium plans.
If you're intent on utilizing Gmail SMTP and still have issues getting squared away, please give us as much information as possible to expedite the support process and help get you back in action. We'll need your alias settings, any errors you're receiving, and any further information you can provide. Screenshots are great!