When the program runs into a crash, it tries to send a message to the guild the crash happened in, or the main server (backup). This often contains a full stack trace of all packages involved. Unfortunately if Rina loses connection to a server (503), it goes through 5 other stack traces as well, ending up with a message of >4096 characters.
A temporary solution was truncating the error messages but better would be to send a second embed or message to send the entire error information.