When you upload to WordPress you may hit a limit. This is set by your PHP settings.
WordPress is built on the code 'PHP'. You can easily change the settings on the Nimbus Hosting platform to increase your Upload Limit. Use this guide to find the PHP page in the platform - https://support.nimbushosting.co.uk/support/solutions/articles/36000020525-changing-your-php-configuration
You can then increase the upload limit from the drop-down shown below:
Once you change the setting it will automatically update.