I just switched my unlocked Pixel 4a 5G from Verizon to Visible. I ordered the SIM card as an iPhone 8 and put it into the phone and everything has worked fine - calls, texts, internet.
But I can't send or receive MMS messages. I tried to look at the APN settings as some other posts suggested, but the only APN option listed is "Visible - VSBLINTERNET", and when I click the three dots menu there is no option to add new APN. Any suggestions?
Try going to settings, reset options and click on Reset Wi-Fi, Mobile & Bluetooth. Then power cycle your 4a. If that doesn't work contact Visible to do a network reset.