The iPhone11 does not support the use of magnetic wireless charging bank.
The same goes for the iPhone 11 promax itself.
For iPhone, only iPhone12 and above versions of mobile phones can use wireless magnetic charging bank, only it can support use, and can charge normally.
However, for your problem, your iPhone11 full series does not support magnetic wireless charging bank, there is no way to charge normally, including your iPhone11Promax.
At present, all Apple products that support wireless charging can be used, but only the 12 series of iPhone products have magnetic and wireless 15W, although the iPhone 11 can be used, but it does not support magnetic and wireless 15W, can only be placed on the same as ordinary wireless chargers with wireless 7.5W charging, but these must be bought by themselves. Apple doesn't give away...