5 year old having accidents

My 5 year old has started having night time accidents again. I don’t know what to do. I’m at my wits end and tired of cleaning sheets. We’ve tried sticker charts, we’ve tried small treats, large rewards, taking things away. Nothing seems to be working. Or it works for a few days, then it’s more accidents. And today I received an email from her teacher saying she purposely peed her pants today. I don’t know what to do. Any advice or tips...anything would be greatly appreciated!! There has been no major life changes. This started last month, 2 months ago? She potty trained by 3years old, fully potty trained (day and night) so she hasn’t had a night time accident in awhile. She would have one here or there but not like this. Help!!!