outlook Mail Send problem

I am having issues sending emails, and this is happening with all of the emails I send. I am not sure if I need to configure settings in order to resolve this issue, so I am looking for someone to help me out. I need an experienced freelancer who can effectively troubleshoot and identify the exact source of the problem and offer a viable solution. The project will involve assessing the current setup of my accounts, troubleshooting and testing any potential solutions, and making sure that the problem is fully resolved.