When you setup a LabQuest 2 to send e-mail, (Home|Connections|Email,) and press the test button, it will send a test e-mail from the LabQuest to the "From" address. If it goes well, it will report "Message sent successfully" but if there is a problem it will report an error code.
The error number by itself isn't normally enough information to diagnose the problem, but under the error message is a little triangle that says "Details". Tap on that and it should list some much more useful information.
In this example we've setup the LabQuest to try to contact smtp.example.edu, (which doesn't exist.)
And the error message says it cannot locate it. If the server existed but the LabQuest couldn't talk to it for a network/firewall reason, the LabQuest would still say error 68, but the details would say something different.
The complete list of error codes are:
#define EX_USAGE 64 /* command line usage error */
#define EX_DATAERR 65 /* data format error */
#define EX_NOINPUT 66 /* cannot open input */
#define EX_NOUSER 67 /* addressee unknown */
#define EX_NOHOST 68 /* host name unknown */
#define EX_UNAVAILABLE 69 /* service unavailable */
#define EX_SOFTWARE 70 /* internal software error */
#define EX_OSERR 71 /* system error (e.g., can't fork) */
#define EX_OSFILE 72 /* critical OS file missing */
#define EX_CANTCREAT 73 /* can't create (user) output file */
#define EX_IOERR 74 /* input/output error */
#define EX_TEMPFAIL 75 /* temp failure; user is invited to retry */
#define EX_PROTOCOL 76 /* remote error in protocol */
#define EX_NOPERM 77 /* permission denied */
#define EX_CONFIG 78 /* configuration error */
(LabQuest is just using the Unix sendmail command.)
TIL 2689: When setting up LabQuest 2 for Gmail/Google Apps, I get an error 77.
TIL 3946: LabQuest 2 e-mail gives a error "code 4" after you enter your password.