When it seems that your previously very reliably pottying baby has forgotten everything about telling you, signalling or signing it can be so frustrating. You may feel that it has all been a waste of time - but do not be deceived!! Sooner or later, everything will get back on track, often with a great leap in reliability.
There are times when misses are more likely:
These are often things that you will figure out after the fact. Small comfort though that may be when you are in the middle of it.
Most importantly -
Maintain your side of the communication
Respect your child's communication - but understand that although they might say they don't need to eliminate, rather it may be that they do not want to interrupt what they are doing for something low priority (to them) like going to the toilet. In this case, when you are certain that they really do need to go, try bringing the potty to them or taking the toy to the toilet.
Give your baby or toddler choices: red potty or blue potty; toilet or potty; before you or after you; inside toilet or out in the garden
Think about what you are saying - if your toddler is doing the potty dance, there is no benefit in asking "do you need to go"! Instead you might say something like: "I see you need to do a wee. Are you going to run to the bathroom or would you like me to carry you?"
Do not stress over it
Consider taking a short break from EC (but only for a day or two) and offer only at the prime time for catches such as when waking in the morning or after a nap etc. Think about taking a step towards greater conservatism in terms of protecting the environment from misses - eg if your baby had been in training pants, you might consider using nappies a bit more
Alternatively, and this is my recommendation, think about taking a leap towards less - eg ditching nappies and moving to training pants, or from trainers to regular underwear. Or bare bottom when in easy clean up areas. Keep a potty nearby.
The "three strikes and you're out" position - after three pairs of wet undies, go back to trainers or nappies for the rest of the day
Try different potty spots - potty, seat reducer, in arms, supported on the toilet seat, outdoors etc
Change up the things that you do with your little one while they are on the toilet - eg new potty toys, books, games and songs
If none of these tips help, please email me.