Hello, @Madeleineseitz! Really sorry to hear about that. So we can further help you, please send us a private message with your number and PIN. Thanks.
Mine was getting the same thing today and I just got my phone recently. It is a Moto g6 play . Recently today and I believe another time I kept getting invalid SIM card. I am wondering how I can get my SIM card replaced if needed.
Recently purchased the Moto G6 Play from Virgin and the sim card it came with was invalid. No LTE connection. Called tech support a few times and the ##72786# phone dial pad reset function did not work. Virgin did not have the correct sim card in stock but included a $10 paypal credit. Stopped by the local Sprint store but they did not have the right sim card#CZ2104TLWQ for the MOTO G6 Play but there were some on Ebay. Called Virgin and registered the new sim card but it still did not work and it was reading invalid again with no LTE connection. Found info online about doing a factory reset in recovery mode. The MOTO G6 Play has the LTE connection now after registering the new sim card and performing a factory reset in recovery mode.