Outlook email not linking with Samsung email

So a bit of background:

• I obtained a domain and email from Blacknight.com.
• I then set this email up on my Samsung email app, using IMAP (this link gave instruction on how to https://help.blacknight.com/hc/en-us/articles/212518689-How-do-I-set-up-email-on-an-Android-device?fbclid=IwAR0Sp_VHJglAiiBYG52vO2SJ64mSyyIdRlVQfqc58s5arnRBQYCtM-gc-bo).
• I then set this email up on Outlook.

Issue:

• The emails do not seem to be linked, it seems like I have the same email address but they seem to be separate from each other.
• If I send an email from Samsung email to anyone, I cannot find this in my outlook sent folder.
• Also, if somebody emails this email address, I only see it in my Samsung email, not outlook.

Has anyone come up against this issue before?