fixed_login authenticator failed for localhost

Email account problem
getting an error as
fixed_login authenticator failed for localhost or
fixed_login authenticator failed for localhost (domainname ) [127.0.0.1]:58923 I=[127.0.0.1]:25: 535 Incorrect authentication data (set_id=test@domainname)
There are two ways for this one you can reset password for email account if still issue not resolved
take backup of email account remove it from cpanel and restore the back
follow the steps:
#cp test test-2
Then remove test account and recreate it from cpanel
Then copy the test-2 directory in to test
some times test-2 directory copied into test then move contents of it to test and remove test directory
cp * -p ../ -R
Done