How to turn off the blue line on iMessage
How to turn off the blue line off iMessages
Are you referring to Spell Check blue line?
It would be better if you can please re-post with a screenshot, in order to understand the phenomenon better. Images/pictures speak louder than words.
Please understand this is a public forum: While attaching a Screenshot, do not provide any personal credentials, such as IP address, Card detail, email id, apple id, IMEI number, Serial Number, Phone number, Order ID, if you are sharing a map ensure your location is not identifiable, etc.
With the limited information that you have provided, It is hard to even guess the problems faced by you.
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Please re-post with detail so that someone else can help.