no mail. just the word “Error”

Hello, in the last week or so i have stopped receiving messages. When trying to send a message form the contact form i just get red ” x error” message. No border, no sentence. Smtp mail test OK. PHP version 7.4. All was working well previously with no back end change other than theme and plugin updates. Sydney theme version 1.67. Contact form 7 Version 5.2.2.

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