[01] 7/27 13:25:00 ~ Status: Opening connection for delivery...
[01] 7/27 13:25:00 --> Connecting socket [1] with 1 entries to smtp.worldpath.net Port:25
[01] 7/27 13:25:00 ~ Status: Connected
[01] 7/27 13:25:00 220 smtp.worldpath.net Exim ESMTP - Unauthorized access is prohibited.
[01] 7/27 13:25:00 > EHLO [192.168.1.104]
[01] 7/27 13:25:00 250-smtp.worldpath.net Hello [192.168.1.104] [63.127.197.21]
250-SIZE 52428800
250-PIPELINING
250-AUTH PLAIN LOGIN
250-STARTTLS
250 HELP
[01] 7/27 13:25:00 > AUTH LOGIN
[01] 7/27 13:25:00 334 VXNlcm5hbWU6
[01] 7/27 13:25:00 > GDTE
[01] 7/27 13:25:00 334 UGFzc3dvcmQ6
[01] 7/27 13:25:00 > ******
[01] 7/27 13:25:03 435 Unable to authenticate at present
[01] 7/27 13:25:03 ~ Status: Unhandled response - 435 Unable to authenticate at present

You have to contact your server support about that. Only them can know why their server no longer accept your credentials.