Can not (de-)activate plugins

Hi there
I’ve been using your theme for a long time and didn’t run into any problems, however lately there seems to be a problem where I can’t find the source. When trying to (de-)activate plugins the error message ‘The link you followed has expired’ comes up. I already reached out to the tech support of my hosting company, even after different escalation levels they weren’t able to solve the problem but told me this:

So this shows an error with the theme (mesmerize) what you using for your website. If we change back the theme to mesmerize and try to access plugin it started to show error once again. I have now reverted the theme to mesmerize. You can check this by switching the theme to default WordPress theme and try to access plugin from your end. You should able to access it without any error. We suggest you to contact theme vendor and ask them to check the issue with the theme, So that they can check the error related to theme and help you to resolve it for you.

Please help, of can provide you with hosting credentials if needed.

Kindly,
Vincent

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