Changed username; now cannot assign tasks to that user

[Laura McCurdy]

At the request of the user, I changed a username from firstname.lastname@emailaddress to firstname.lastname. The user can log in and work fine within Jira (7.2.2), but we can no longer assign tasks as we get the following errors in Chrome: 

The JIRA server was contacted but has returned an error response. We are unsure of the result of this operation.

When I click OK on the errror dialog box, the following errror appears: 

An error occurred

Please try refreshing the page, or contact your administrator / Atlassian Support if the problem continues.

Details
Exception: Uncaught TypeError: Cannot read property 'value' of undefined

I have attempted to revert back to the old user name. Same error. 

I have cleared Login Tokens for the acct. Same error. 

I have deactivated and reactived the acct. Same error. 

Any other ideas before I just create a new user acct (really don't want to lose the user history)?

[somethingblue]

Hi Laura,

Based on the error you've presented you may also see a line such as the following:

Caused by: java.lang.IllegalStateException: User 'xxx' has no unique key mapping.

If you do see the above line you'll want to follow the guidance in JIRA Login fails with 'User exists but has no unique key mapping' because that means one of the fields in the cwd_user_table may not match the name you changed it to.

Cheers,

Branden