email not being received at destination.

I am using Windows Mail. Until a few days ago I had no problems. Brighthouse is the internet provider & Road Runner is the email provider. I am able to receive messages but if I send a message it shows in the sent box but doesn’t arrive at its destination. I have spent 5 hrs with Microsoft & 2 hrs with Road Runner & the problem is not solved. My question is if I download eM Client to see if messages go through using that software will Windows Mail still be available until I decide what I should do?

Yes, it will be available as eM Client has no effect on the other installed applications.