Sharepoint workflow designer call web service

https://[siteurl]/sites/dev/_api/web/siteusers(@v)?@v=%27i%3A0%23.f%7Cmembership%7C[username]%40mydomain.onmicrosoft.com%27

I called this web serive to get the user id, but the workflow stopped.

Error :

Retrying last request. Next attempt scheduled in less than one minute.
Details of last request: HTTP InternalServerError to
https://[sitesurl]/sites/dev/_api/web/lists(guid’68a69104-957e-4de3-ad44-878e55253f8e’)/Items
Correlation Id: d96d0819-7175-0401-8825-894ffceb9552 Instance Id:
45b15e4a-616f-41c2-871b-6d0cae099206

Invalid text value.

But I can enter it by my browser.