UUID TX RX ionic / iphone

Good morning, we are doing an app in ionic where you can print labels on a ZQ510 printer. On the Android side I have no problems since the tag comes out correctly, but on the iPhone side no.
We were able to make the iPhone find the printer by BlueToothLE, we do a connection test and it is successful, but it does not print. The printer is not receiving the information.

These are the uuid services we are using:
#define HM10_SERVICE_UUID "FE79" // -> by putting this key we were able to make the mobile connect to the printer.

#define HM10_CHAR_TX_UUID "38EB4A82-C570-11E3-9507-0002A5D5C51B"
#define HM10_CHAR_RX_UUID "38EB4A81-C570-11E3-9507-0002A5D5C51B"

We believe that these last two are not letting us print.

If someone has the correct TX_UUID and RX_UUID, we would appreciate it if you could pass it to us.