Pixel 4 sends MMS messages endlessly

I have a new Google Pixel 4. For as long as I've had the new phone (several weeks), photos and gifs will not send properly. I'm using the standard Android Messaging app. My phone continues to say "Sending..." below the photo even though the recipient has received it. This continues, with the recipient receiving the MMS upwards of 20 times, until I manually delete the message my phone is still trying to send. This happens to any recipient, both at home connected to our MicroCell and outside the house connected to the general mobile network. Has anyone else had this issue or know what would cause it? Thanks!