I need help with these errors on my whmcs installation.

[desdag]

Oops!

Something went wrong and we couldn't process your request.

Please go back to the previous page and try again.

For additional assistance, please reference the WHMCS TroubleShooting Guide »

Error: Method WHMCS\MarketConnect\Promotion\Promotion::__toString() must return a string value in /home4/s2hostyj/public_html/clientarea/vendor/whmcs/whmcs-foundation/lib/MarketConnect/Promotion.php:0
Stack trace:
#0 /home4/s2hostyj/public_html/clientarea/vendor/whmcs/whmcs-foundation/lib/MarketConnect/Promotion.php(0): WHMCS\MarketConnect\Promotion::renderPromotionsCarousel(Array)
#1 /home4/s2hostyj/public_html/clientarea/vendor/whmcs/whmcs-foundation/lib/Hook/Manager.php(0): WHMCS\MarketConnect\Promotion::WHMCS\MarketConnect\{closure}(Array)
#2 /home4/s2hostyj/public_html/clientarea/vendor/illuminate/support/Facades/Facade.php(261): WHMCS\Hook\Manager->run('ClientAreaHomep...', Array, false)
#3 /home4/s2hostyj/public_html/clientarea/includes/functions.php(0): Illuminate\Support\Facades\Facade::__callStatic('run', Array)
#4 /home4/s2hostyj/public_html/clientarea/clientarea.php(0): run_hook('ClientAreaHomep...', Array)
#5 {main}