oracle – UTL_HTTP.get_response is not able to read special character in Supplier name

Im making a call to JSON based REST API from plsql.

When ever there is special character in Supplier name , UTL_HTTP.get_response gives error- ORA-29268: HTTP client error 400 – Bad Request
for example if supplier name has any of these special characters – (à,À,á,Á,â,Â,ã,Ã,ä,Ä,å,æ,œ,ç,ð,ø,¿,¡,ß). then it throws error – ORA-29268: HTTP client error 400 – Bad Request
Note- i have enabled UTL_HTTP.Set_Response_Error_Check ( enable => true ); and
UTL_HTTP.Set_Detailed_Excp_Support ( enable => true );

I tried to UTL_HTTP.SET_BODY_CHARSET(‘UTF-8’);— but still it didn’t help

My database NLS character set – UTF-8

Any quick highly appreciated.

Thanks
Lohitha