Etag value not valid on PUT request

Hello,

i am having problems trying to update records through NAV 2015 OData WS.

I am getting: "The etag value '28;X8MAAAJ7/0EARAAwADAAMQAAAAAA9;7238058930;' specified in one of the request headers is not valid. Please make sure only one etag value is specified and is valid."

This is what i get if i do a GET:
GET http://*******:****/****/Odata/Company('***')/Socios('AD001')?$format=json
{
"odata.metadata": "http://*********.es:****/******/OData/$metadata#Socios/@Element",
"N_x00BA_": "AD001",
"Nombre": "JESUS",
"ETag": "28;X8MAAAJ7/0EARAAwADAAMQAAAAAA9;7238058930;"
}

I am trying to update with this call:

PUT http://********.*****.es:****/*****/Odata/Company('****')/Socios('AD001') HTTP/1.1
Accept-Encoding: gzip,deflate
Authorization: Basic bGlmZXVzZXI6QXRhbWExYXRhbWEx
OData-MaxVersion: 4.0
OData-Version: 4.0
If-Match: 28;X8MAAAJ7/0EARAAwADAAMQAAAAAA9;7238058930;
Content-Type: application/json
Accept: application/json
Content-Length: 107
Host: **********.*****.es:****
Connection: Keep-Alive
User-Agent: Apache-HttpClient/4.1.1 (java 1.5)
{
"N_x00BA_": "AD001",
"Nombre": "JESUS",
"ETag": "28;X8MAAAJ7/0EARAAwADAAMQAAAAAA9;7238058930;"
}

Can i get some help?

Thx you very much.