Just taken delivery of ampkit link. I can hear the metronome and the dry pre-recorded stuff from the app but I am getting no guitar input or sound output. Tried pulling the guitar jack in and out of the socket slightly and checked the input gains which are at 50% but no good. From a google search i see that a few people have this problem. App problem or malfunctioning ampkit link ? Thanks Scott

SOURCE: I've just got an ampkit

If you touch the area where the input and output level bars are (lower right of the screen) it will open a page called "Input Options".
Make sure the input and output gains are up about 75%. Usually the output gain is about 5-10% lower. If you're getting a button that says "No Input" where the input/output level bars should be on the lower right corner, it is telling you that your iPhone headphone/mic jack is not sensing the line from the Amplink. Leave everything connected, and exit the Ampkit program and then start it again. It should reopen with the level indicators showing. These connections are all finicky.

SOURCE: when the ampkit link is

Best in this case is to get in touch with the company - there should be an "Info" panel, and a Feedback section where you can contact them directly.