Zoho account no longer beig received in Apple Mail

One of our Zoho accounts is being operated using Apple Mail on MacOSX Yosemite and also on an iPhone 6S. There has been no recent changes to the account settings and sending and receiving mail is still continuing to work on the iPhone without disruption.

However via Apple Mail the account still operates to send email without difficulty but will not not receive email. Using the Connection Doctor the following log details are consistently listed:

INITIATING CONNECTION Dec 26 23:59:33.502 host:pop.zoho.com -- port:995 -- socket:0x0 -- thread:0x60000107f480

CONNECTED Dec 26 23:59:35.042 [kCFStreamSocketSecurityLevelTLSv1_0] -- host:pop.zoho.com -- port:995 -- socket:0x6080008b8540 -- thread:0x60000107f480

READ Dec 26 23:59:35.042 [kCFStreamSocketSecurityLevelTLSv1_0] -- host:pop.zoho.com -- port:995 -- socket:0x6080008b8540 -- thread:0x60000107f480
+OK POP3 mx.zohomail.com v1.0 server ready < 362837.1451134774590@mx.zohomail.com>

WROTE Dec 26 23:59:35.042 [kCFStreamSocketSecurityLevelTLSv1_0] -- host:pop.zoho.com -- port:995 -- socket:0x6080008b8540 -- thread:0x60000107f480
CAPA

READ Dec 26 23:59:35.411 [kCFStreamSocketSecurityLevelTLSv1_0] -- host:pop.zoho.com -- port:995 -- socket:0x6080008b8540 -- thread:0x60000107f480
+OK

READ Dec 26 23:59:35.719 [kCFStreamSocketSecurityLevelTLSv1_0] -- host:pop.zoho.com -- port:995 -- socket:0x6080008b8540 -- thread:0x60000107f480
USER
.

WROTE Dec 26 23:59:35.725 [kCFStreamSocketSecurityLevelTLSv1_0] -- host:pop.zoho.com -- port:995 -- socket:0x6080008b8540 -- thread:0x60000107f480
USER dion.weston@iComplain.com.au

READ Dec 26 23:59:35.969 [kCFStreamSocketSecurityLevelTLSv1_0] -- host:pop.zoho.com -- port:995 -- socket:0x6080008b8540 -- thread:0x60000107f480
+OK

WROTE Dec 26 23:59:35.972 [kCFStreamSocketSecurityLevelTLSv1_0] -- host:pop.zoho.com -- port:995 -- socket:0x6080008b8540 -- thread:0x60000107f480
PASS ***********

READ Dec 26 23:59:36.334 [kCFStreamSocketSecurityLevelTLSv1_0] -- host:pop.zoho.com -- port:995 -- socket:0x6080008b8540 -- thread:0x60000107f480
-ERR Authentication failed

WROTE Dec 26 23:59:36.334 [kCFStreamSocketSecurityLevelTLSv1_0] -- host:pop.zoho.com -- port:995 -- socket:0x6080008b8540 -- thread:0x60000107f480
QUIT

READ Dec 26 23:59:36.642 [kCFStreamSocketSecurityLevelTLSv1_0] -- host:pop.zoho.com -- port:995 -- socket:0x6080008b8540 -- thread:0x60000107f480
+OK mx.zohomail.com Service closing transmission channel

We've reapplied the password to the account settings (no change to the password) but the problem persists. We've restarted the Mac again with no improvement.Any hints as to how we might clear this blockage would be most gratefully received.