What "other connection" causes Error code: 0x516 using Remote Desktop

Question

Of the three previous questions referred to, none have been resolved, so I don't know if this error was resolved, or the questioners just gave up (how I'm feeling).

Does "other connection" mean having the RD app and RD store on my home computer (not the host), or is it another program? On the host I have Laplink for file transfer (which will no longer connects since setting up RD) and Shut Down Expert to hibernate the office (host) computer of an evening.

In Task Manager there is no PID associated with Laplink, so I don't know if it is using the same port 3389.

It's difficult, because I have to go to the office to make a change, then come back home to see if it was effective. If not, go back to the office and try something else. I've been doing that for two weeks now.

I don't have the internet at home, so I tether with my mobile to connect to the office.

(Later)

I disabled Laplink, Shut Down Expert, and turned off McAfee Firewall on the host computer. Tried to connect and got the box saying cannot connect to the remote computer (I know the host computer is on, I just left it).

Answer 1

Hi. Thank you for your question and reaching out. I’d be more than happy to help you with your query.

Error code 0x516 when attempting to connect via Remote Desktop typically occurs when there is a communication problem between the server and the client. This can be caused by an incorrect IP address, an inactive or blocked port, or an incompatible authentication protocol. It may also be caused by an active connection to the server by another user, which can block the connection attempts from the client. To resolve the issue, check the IP address, confirm that the port is active, and verify that the authentication protocols are compatible. Additionally, check for any other active connections to the server that may be causing the issue.

If the reply was helpful, please don’t forget to upvote or accept as answer, thank you.

Answer 2

Thank you for your answer.

After yesterday’s efforts turning off Firewall, Laplink, and Shut Down Expert, then turning them back on, I now get the message “Remote access to the server is not enabled”

Taking your suggestions in turn:

Incorrect IP address:

Did a search for “What’s my IP” in Bing.com and I enter that IP in the Remote Desktop Connection App

An inactive or blocked port:

On my home computer advised to “Open a command prompt window as an administrator, change to the directory in which you installed psing, and then enter the following command: psing -acceteula <computer>:3389 Then check the output of the psing command results.

I can download psing but I don’t know how to install it in a directory. So I’m a bit stuck here unless there’s another way to check an inactive or blocked port.

Incompatible authentication protocol:

Don’t know what that is. Is it the username and password? Or do you mean the RDP protocol. I did go to the registry key path …\Terminal Server and double-clicked the fDentTSConnections and it is set to 0

active connection to the server by another user

There are no other users, just me. I do have a non-administrator account, and a second administrator account, but I only use one at a time.

Answer 3

SOLVED!

First solution: In router admin account accessed via 192.168.1.1 and set DMZ to "Enabled", RMD worked great for about six weeks, then could no longer connect due Error 0x516.

Second solution: Again, to do with the router. Dynamic IP address had changed. So just entered new public IP address in port 3389 forwarding rule. Had to reboot router.