Lora E22 stops sending after some time

Hello, I have been testing communication between two LoRa e22 devices, using "LoRa_E22.h" library, and I have noticed that after a certain number of packets the sender module stops working. I have tried all kinds of software solution, but nothing seems to work, not even reset the arduino makes it send again. The only thing that works is to disconnect and connect the 5v on the LoRa module (hard reset). I found interesting the fact that when I'm sending a packet with 15 characters the module works for 42 times (fixed transmission), but if I send a packet with 7 characters, the module works for 80 times. Which makes me think that the problem starts to occur when the buffer gets full (1000 bytes). I wonder though, wasn't the module supposed to clean its buffer after a packet is sent? Is there a alternative way to clean the buffer without having to hard reset the LoRa? The codes are extremely simple, just a standard fixed communication, just like in the examples.