SMPT Authentication Problem

[ashoksharmaz87]

Hi,
I am getting the following error while accessing my hotaru based bookmarking site http://readandrefer.com

authentication failure [SMTP: Invalid response code received from server (code: 535, response: Incorrect authentication data)]

Please someone suggest the possible solution..

[frytec]

check if the user name you are designating to the sender email address contains invalid characters, usually this error comes up when you use dots on the user name of the sender.
Like:

MySite.com <admin@mysite.com> invalid sender name
MySite <admin@mysite.com> valid sender name

[ashoksharmaz87]

Thanks frytec for your reply
My site was working well and it suddenly started showing this error message. Can you please tell me in a little detail where exactly I need to make corrections?

[frytec]

Exactly where/when (what plugin) is throwing that error?