How do I login to my 2 ec2 instances from Android mobile as I can only login from Desktop?

Any given Windows server has a default limit of 2 concurrent inbound RDP connections. This is a Windows default limit, not an AWS limit, and AWS doesn't have any other RDP limits. No license is needed. You should be able to connect from Android with an RDP client. What happens when you try, timeout?

Are your EC2 instance's Security Groups open inbound to your Android's IP address? Are their subnet NACLs open completely, or open inbound to your IP + suitable ephemeral ports outbound for an Android client?

Can you Ping your EC2 instances from your Android (after allowing this in your Security Groups & NACLs)?

Are your existing desktop PC connections also connecting over the Internet or via DX or site-to-site VPN?

To help narrow things down have you tried connecting your desktop PC to the internet via hotspot on your phone?

inbound rules source 0.0.0.0/0

When I try it times out but not sure I am using the correct login details, I am using same login as is for my computer, but I did have a pem file and it was to create login for desktop

I did copy pem onto mobile but it did not make any difference

Maybe I need to create new pem file on mobile?

Subnet acls open completely, not sure where to find that, will need tp read up a bit more

Again I will need to read up on pinging to see how to ping it from the mobile

The only way I tried to connect to the server was from Desktop pc using rdp, I am not sure on all the other stuff, will need to read up on it

I never tried connecting pc via hotspot on the phone but I will have a go at that

Thanks for your assistance, I definitely have more reading to do in order to fully understand