How to fix changeip Authentication error. (Error code: 2)?

Balance 310 running 5.4.9 build 1564

WAN1: DDNS domain update failed. Authentication error. (Error code: 2)

I have re-entered both the username and the password.
I have used the same credentials to logon to without any error.
The Dynamic DNS Update History there is empty.

What does Authentication error. (Error code: 2) mean for the service?
And/or how to fix this error?

The solution is to change your password, and replace punctuation character ‘colon’ == “:” by something else.

This issue might be caused by a bug in the Peplink software not allowing to correctly transfer the entered password (containing a colon) to the remote DDNS service provider.

Thanks for spotting this. Moving this to Feature Request for supporting colon :, DDNS, password field.