Quick reply: context=default, extension must match one of your carrier dialplan entries. If that includes a country or long distance code/prefix, you must include that in addition to the number to match the dialplan. In the US, for instance, I would enter "913522690000" where 9 is the dial prefix (used to select the carrier) and 1 is the domestic long distance code, and 3522690000 is the actual 10 digit US phone number. Our dialplan pattern for US numbers is "_91NXXNXXXXXX". Note the 9 and 1 hard-coded into the pattern.
Full response:
1) Please remember to include your installer with full version information in your post or footer. It helps.
2) This is not actually a "goautodial" question. Goautodial is merely the "installer" for Vicidial. This was a Vicidial Support question, unrelated to the installer. I'll move the post to the Support board accordingly.
3) There is more in-depth information regarding the call menu configuration options in the Vicidial Manager's Manual which is available in both Free and Paid versions on eflo.net's store.
Happy Hunting!