Possible causes:
If you are connecting to JIRA Cloud, make sure that you are using your e-mail as the user name and a valid Api Token as the password with the Auto or Basic option. Do not enter your actual JIRA Password. There is a link in the Connection Settings form to the article that explains how to generate an Api Token.
If you are connecting to JIRA Server, your login or password is incorrect. Check the username, re-enter the password and try again.
The JIRA URL starts with HTTP for a secure server, e.g. http://myjira.atlassian.net. Change it to https: https://myjira.atlassian.net. Always use HTTPS for JIRA Cloud.
If you are connecting to JIRA Cloud, please update to Ceptah Bridge 3.6.5 or newer or tick the 'Always use basic authentication' option in the connection settings.
Be mindful of the fact that there are global and project-level settings. The latter override the former, if provided. Make sure that you are testing the settings in effect.
The most common cause of this error is a locked JIRA account. It gets locked after a few attempts to log in with invalid credentials. To resolve the issue, do the following:
Open the effective connection settings, check the login and re-enter the password. You need to fix the password before unlocking the account. If you try to open the project settings while the password is invalid, the account will be locked again because Ceptah Bridge will try to access JIRA with the wrong credentials.
Log in to JIRA through the web UI in the browser. If you are logged in, log out and log in again. If JIRA has added the CAPTCHA test to the regular log-in screen, that means that the account is locked. After you have logged in, the account will be unlocked.
Test the connection in Ceptah Bridge and save the settings.
Click here for Offline Activation.
With Ceptah Bridge prior to version 3.8, in 99.99% of cases this is because the bitness of your MS Project is different from the bitness of the installed Ceptah Bridge package. If you are using Ceptah Bridge 3.7 or earlier and MS Project 2000, 2003, 2007 or the 32-bit version of 2010, 2013 or 2016, the 32-bit package needs to be installed even if the Windows is 64 bit. For MS Project 2010-2016 64 bit, use the 64-bit installer. No matter how confident you are that you are running the correct version, please go to FILE > Account > About Project and double-check. It will be right at the top.
If the bitness does not match, uninstall the product and install it using the right installer. Make sure that you uninstalled the other package before installing the correct one because failing to do so may create issues as well.
Also, the following may cause the problem.