One of the frequent reasons for issues with JIRA Client is using HTTP protocol in the connection settings instead of HTTPS. Some of the JIRA Client functions would still work over HTTP, but with some actions you will be getting errors.
The best way to switch from HTTP to HTTPS is as follows.
This method will require rebuilding your database (which means you will need to have the Internet connection to do it). If you wish to change connection URL without reloading database, please refer to this article: https://wiki.almworks.com/display/jc16/How+to+change+the+URL+of+a+Connection
- Create a new connection with the correct protocol (https://).
- In the navigation area select the queries of the old connection that you would like to copy to the new connection (you can select multiple queries using SHIFT and CTRL).
- Press CTRL+C (or right-click | Copy) to copy the queries to the Clipboard.
- Select the new connection and press CTRL+V (right-click | Paste). Your selected queries will be added.
- Remove the old connection.
- Run the queries to download the issues to the local database.