Class "String" does not exist swagger magento 2

Question

I am working with swagger api but when hit this url :-

http://localhost/magentosetup/swagger

I get the error when I am trying to use api please help. :-

500 : {"message":"Class \"String\" does not exist. Please note that namespace must be specified.","trace":"#0 \/mnt\/data\/home\/134855.cloudwaysapps.com\/etfeurwasq\/public_html\/vendor\/magento\/framework\/Reflection\/TypeProcessor.php(212): Magento\\Framework\\Reflection\\TypeProcessor->register('String')\n#1 \/mnt\/data\/home\/134855.cloudwaysapps.com\/etfeurwasq\/public_html\/vendor\/magento\/framework\/Reflection\/TypeProcessor.php(181): Magento\\Framework\\Reflection\\TypeProcessor->_processMethod(Object(Zend\\Code\\Reflection\\MethodReflection), 

Answer 1

In my case this error occurred when setting an extension attribute value with a wrong type where type string was expected.

Aligning the extension attribute value type with the expected type fixed the issue.