@Garylaing
It's a common issue with O2 as they do not support delivery reports.
The software used by phones to determine delivery is not compatible so just defaults to a failure message.
Sometimes, starting each text with *0# will give the correct status.
I have no affiliation whatsoever with O2 or any subsidiary companies. Comments posted are entirely of my own opinion. This is not Customer Service so we are unable to help with account specific issues.
Please select the post that helped you best and mark as the solution. This helps other members in resolving their issues faster. Thank you.
