This error generally happens when rdpclip has become unstable. To solve this issue you can simply restart the rdpclip.exe application.
To do this open task manager, click on "Details" then find rdpclip.exe

Now end task on rdpclip.exe
Next you can restart the rdpclip.exe by running a new task

Enter rdpclip and click "OK"

That's it, your done and the problem should be solved.
If you have not already, you can download PuTTY from putty.org
Once you open PuTTY you can input the mail server name or IP address you are attempting to connect to into the Host Name field. Then update the port to 25 and the connection type to "Telnet".

When you click connect you should see something like this:

Other responses:
- If you do not receive a response, the connection was blocked by the mail server.
- If you receive "Cannot connect to host on port 25" the mail server is likely offline or is having network routing issues.
You can also run a few commands to test
You can quickly bypass this error by using robocopy,
use run as administrator to open a command prompt and do the following:
robocopy /e /is /v /eta [driveletter]:\sourcefolder [driveletter]:\destinationfolder
/e Copies all subdirectories.
/is Includes the same files.
/v Produces verbose output, and shows all skipped files.
/eta Shows the ETA of the copied files.
This error is caused because 3dm2 uses a no longer supported SSL cipher. Normally in order to fix this issue you would just issue an updated SSL cert but 3DM2 does not offer this option, so you will need to open up a legacy browser.
On windows you will need to run internet explorer

then open the local server address, https://localhost:888/
It is possible you will need to go into internet explorer > internet options > advanced and enable addition SSL protocols as well.

In some cases Sprint phones do not work correctly on the T-Mobile Network after installing a T-Mobile SIM card and need to be manually configured.
Here are the settings you will need to use in order to update your phone to have data service again.
- Go to Settings > Network > Mobile Networks
- Select Access Point Names (APN)
- Use the menu in the upper right to "Add APN" and Set the following:
Name: T-Mobile
APN: fast.t-mobile.com
MMSC: http://mms.msg.eng.t-mobile.com/mms/wapenc
APN Type: Internet+MMS or in some cases default,supl,admin,dun,mms
(Leave everything else to defaults)
- Now go to Settings > Network > Network Settings Reset(in some cases "Network Reset"
- Then Chose "Reset Settings" and it will require you to enter pattern or unlock code.
- Click "Reset Settings" again.
Known Issues:
- This will not fix the connecting to network authentication issues.
- This will not fix the Update PRL or Update Profile authentication issues.
- This will not update your phone number in the about phone area under settings.
If you continue to have issues, call support and talk with a supervisor. The standard support has no clue how to fix these issues.