White space on webpage

I have recently published my website. However, sometimes the web pages load as they should but at other times I get white space. Sometimes the white space is at the top of the page underneath the header, sometimes its further down the page. I can’t figure out what is causing it as it doesn’t always happen. The white space is as though someone has added an extra row.

I hope this explains the issue well enough for support. I have a screenshot if it would help.

David

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