In November 2022, PHP 7.4 reached EOL. This means that any software (such as WordPress themes & Plugins) that haven't received compatibility updates from their upstream developers, may not be compatible with the latest PHP version.
Unfortunately, this has caused some websites to break.
A quick fix is to enable debugging, or to check the logs in your control panel, to identify which software is causing the incompatibility and disable it.
In some cases I've identified, the website itself may need to be rebuilt into a compatible software.
If you are on a managed WordPress plan, I will be in touch with a proposed solution.
If you are on standard hosting, please reach out to us via the support channels with any issues you may have, and we will look at a solution for you.