Iphone not searching through all messages

Hi,

I have the following (big) problem. For me messaging (using sms) is very important. A few days ago i wanted to search for an old sms using the search bar on top - something i do frequently - but only received results from messages from the past 10 days or so. I googled some sollutions but could not find this exact issue. Someone mentioned changing the language, which i did, but that did not work.

I have an iphone se, with up to date software.

Thank you very much, any input is much appreciated.