About 2 months ago in [url=http://logmett.com/support-forums/6/several-observations-while-using-tera-term-for-routine-task-automation-2949]this post[/url] I wrote If SSH login fails due to incorrect credentials testlink command is not able to identify it. The macro goes into waiting loop and there is no indication of what happened. Only after terminating the macro and closing Tera Term main window the error message appears saying that user credentials were invalid. I expect the same will happen if authentication method (password, challenge, etc) is incorrect, but I have not tested that. There should be a better way to handle such scenarios.
Today I experienced this error without running a macro. The easiest way to reproduce it is by opening SSH1 session to the server accepting only SSH2 connections. While this may seem as unlikely scenario, I'm bringing it as an example, just because it is the easiest. As I've mentioned earlier the same is observed during macro execution with incorrect credentials.
Basically, the error message notification will not show until the main Tera Term window is closed. By retrying such invalid connection I was able to generate several hidden error messages that showed up all together only when the application's main window was closed.
Looking at the bigger picture, I think it is time to revisit entire login process. Other modern terminal emulators like Putty, SecureCRT, or MobaXTerm, do not ask user to do so many choices while establishing SSH connection. They are able to auto-detect the protocol version and choose the right authentication method (passphrase, challenge, private key etc.). The less user interaction means better user experience and also simplifies error handling.