No keyword with name '=' found in robot

When using the "=" for variable assignment with the space-separated format, you must make sure you have no more than a single space before the "=". Your first example shows that you've got more than one space on either side of the "=". You must have only a single space before the = and two or more after, or robot will think the spaces are a separator between a keyword and argument.

For the "keyword must not be empty" error, the first cell after a variable name must be a keyword. Unlike traditional programming languages, you cannot directly assign a string to a variable.

To set a variable to a string you need to use the Set Variable keyword (or one of the variations such as Set Test Variable). For example:

${reqresstr}=      Set variable  ${response['_object']}