Error codes that appear while using Skype inform you of a problem that inhibits you from completing the action that you were attempting. Skype has several error codes with descriptions to provide information about what went wrong. Internal errors are generally caused by problems within the Skype's program.
Blocking the Caller
You may see an internal error code in Skype if you inadvertently block the user that you're attempting to reach after you've already initiated a call. While this error is prompted by a user action, the program calls it as an internal error because it can't complete a started call to a blocked user. An external error occurs when you attempt to call a blocked contact after the contact is blocked. Check that the person you're attempting to contact isn't blocked and attempt your contact again.
Call in Progress
If you're attempting to call one of your contacts and receive an internal error message, someone else may be trying to contact that person at the same time. The program will accept the earlier call, and the later caller will receive an internal error message, since two calls can't be completed to the same user simultaneously. An external error would occur if you were attempting to call a contact that didn't exist.
Some internal error messages are created when Skype experiences a glitch and the program is unable to complete the action that you've requested. These errors aren't created on your end. They may be bugs within Skype's programming or temporary errors caused by server issues. If the problem is on Skype's end, you may need to contact customer service for assistance in troubleshooting the internal error messages.
Internal error messages that contain code numbers indicate that you're running an outdated version of Skype. Visit Skype's homepage and upgrade to the most recent version. Error codes occurring while you're running the most recent version state the error without a numerical ID for the issue. Simply upgrading the software may resolve some of the problems that cause internal errors. If you experience further trouble, contact Skype to troubleshoot the cause of your errors.