Parse error: syntax error, unexpected '<' in /homepages

Hi all, without making any updates to my Avada theme in many months yesterday my site went kerpluee all by itself and gives me this error:

Parse error: syntax error, unexpected ‘<’ in /homepages…wp-content/themes/Avada/header.php on line 1923

Any ideas on what I can do to get my site up again.

Many thanks in advance for any help.

Warmest,

Kevin