When you send an email with CorpNote, your email address is used as the 'from ' and 'reply to' email address.
Your email administrator might have an email filter in place that is blocking incoming emails that say they're from a company email address, but are recognized as being sent from another email server. While this is a legitimate practice for third-party email services like CorpNote, it's also a trick that's used by spammers called "spoofing".
You will need to contact your email administrator and ask them to white list (allow) emails from the CorpNote email server.
What to tell your email administrator:
Email messages sent through CorpNote are being rejected due to failing the Sender Policy Framework (SPF) lookup. The sending domain's SPF record does not include the sending IP address being used to relay the email. Please add the following server information to your domain's DNS to approve CorpNote as an email sender for our domain:
DNS Record Type: TXT
Value: v=spf1 include:spf.corpnote.com ~all
TTL: 3600 seconds or 1 hour
Your domain may have other entries in its SPF record, in which you will only need to add include:spf.corpnote.com directly after v=spf1
If you previously added an SPF entry for CorpNote's mail server, you can safely remove ip4:188.8.131.52 from your record during this time, as the include statement will also contain this address.