Good find 
Is there any possibility of configuring your application to consistently use TLS1.2? That would be the ideal for security reasons.
And did you enable it by editing the deployment configuration and changing it as follows?
But yes, in theory Atlas can still support TLS1.0 - if that’s been enabled in the cluster settings (as above) but it’s not being accepted for those incoming connections I’d suggest opening a support case (top right in Atlas) and see if our support folks can help take a look at things from the Atlas end of things.