Emails from criptext domain to custom domain aren't recieved

**Describe the bug**
If an email is sent from the Criptext account (ie user@criptext.com) to a custom domain that is also attached to the account (ie mail@user.com) or vice-versa, the email is added to the sent folder but is never received in the inbox. I believe it could be a server-side issue as it also happens on the Android client.

**To Reproduce**
Steps to reproduce the behavior:
1. Add a custom domain to your Criptext account (ie mail@user.com)
2. Compose a new email from your Criptext account (ie user@criptext.com) to your custom domain (ie mail@user.com)
3. Subject, content or attachments are optional as this bug still occurs with any of these present.
4. Send the email.
5. Refresh/Synchronize the inbox.
6. No new emails from your Criptext account will appear.

**Expected behavior**
A new email from the Criptext account to the custom domain should appear in the inbox

**Device and System information (please complete the following information):**
- Device: HP Pavilion Touchsmart 14-n055sa
- OS Version: Windows 10 1803 (Build 17134.1488)
- App Version: 0.29.0

**Additional information**
Emails sent to a different email provider/domain aren't being received from the custom domain either but I believe this may be a separate issue.