why can't my friend see my text?

[AC Question]

My friend has an iphone. I can see her texts to me but all of a sudden she can not see my texts to her.

 

[ManiacJoe]

You:
Which phone?
Which version of android?
Which carrier?
Which SMS app?

Her:
Which phone?
Which version of iOS?
Which carrier?
Which SMS app? iMessage?

What extra info do you get if you turn on the delivery receipts?
Are you sending pure text, or including emojis and/or pictures?

 

[ManiacJoe]

You:
Which phone?
Which version of android?
Which carrier?
Which SMS app?

Her:
Which phone?
Which version of iOS?
Which carrier?
Which SMS app? iMessage?

What extra info do you get if you turn on the delivery receipts?
Are you sending pure text, or including emojis and/or pictures?