Sometimes, you may face transactional rfc issues in SM58 (like connection error/SQL errors/Application error/System error etc). In those cases, you want to delete those problematic rfc entries. So, please proceed as follows for deleting those entries.
Login to SAP system ABAP stack and navigate to SM58 transaction as shown below. Select the display period and username as per your requirement and execute by clicking on highlighted icon below.
For example, there are 2 transactional rfc errors (similar to below screen)