Charging issue from battery pack

[Randonneur]

I have a battery pack that is rated for 5V and plugs into a phone.
It is important that I can use this pack as it attaches to my bike dynamo.

When I switch the phone on when battery on and plugged in, then the phone shows the charging icon at the top, but when I look into settings its not actually charging. This battery pack charges other phones and other battery packs with no problems.

 

[isdaako]

Is that using the stock cable? If not try that.