@Mowmoore
It's an issue due to the end to end encryption that WhatsApp uses.
After you reinstall or transfer WhatsApp it needs to create a new encrytion key and this can only be done when both users are online at the same time. If this doesn't happen after a period of time, it will time out and the message won't be sent.
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.
