Text message

Hi there,

Sending a text via iMessage will appear blue. Your iPhone tried to send the text via iMessage, but failed, so instead sent it via SMS. SMS messages appear as green. This does not mean that you have been blocked

You can find out the difference between sending messages via iMessage and SMS here: https://support.apple.com/en-us/HT207006

You will never know when you are blocked. You can only guess. This change of colour does not give any indication of blocking.