не могу зайти на ссылку Не могли бы вы написать алгоритм решения проблемы )

Solution

This is not an error in the Web Application Designer.

When such an RFC-connection error occurs, the call from the Web Application Designer frontend to the backend has not worked or not received a result. In most cases, this means that the requested operation could not be performed.

It may be that only the current call has failed, while the connectivity in general is set up correctly. This may be for example, if the maximum number of concurrent connections for the Portal is reached at the moment.
For that reason, please wait a few moments or minutes, and try again to see whether the operation can be performed then.

In most cases, however, the connectivity is not properly configured, so the call will not return a result also during the second and all following tries.
In that case please ask your system administrator to set up the ABAP->JAVA and JAVA->ABAP connectivity in a valid way (at least for your user...).