A method comprising: managing at least one connection between at least two parties (1; 11; 41) via a communication network, wherein when an established connection is to be released, the method comprises determining (S10, S20), in a proxy call session control function (5; 13; 34), an unavailability of radio resources for the established connection of a party (1; 11; 41) and generating (S30; 120; 220), in the proxy call session control function, a connection terminating message (130; 230; 40) to be sent to at least one of the at least two parties, wherein the connection terminating message is provided with an information element indicating a reason for a connection release and indicating the unavailability of radio resources, and includes a reason header field as the information element indicating the reason for the connection release, wherein the reason header field comprises a protocol information portion and a text portion understandable for a user and identifying the reason indicating the unavailability of radio resources, wherein the generating comprises generating the connection terminating message on the basis of a request identifier, a first information portion specifying a recipient of the request, a second information portion indicating the identity of the initiator of the request, a third information portion indicating a unique identifier to group together a series of messages, a fourth information portion identifying and ordering transactions set to the CSeq value that was stored for the direction from the calling to the called user, incremented by one, and a fifth information portion indicating routing information towards a party. managing at least one connection between at least two parties (1; 11; 41) via a communication network, wherein when an established connection is to be released, the method comprises determining (S10, S20), in a proxy call session control function (5; 13; 34), an unavailability of radio resources for the established connection of a party (1; 11; 41) and generating (S30; 120; 220), in the proxy call session control function, a connection terminating message (130; 230; 40) to be sent to at least one of the at least two parties, wherein the connection terminating message is provided with an information element indicating a reason for a connection release and indicating the unavailability of radio resources, and includes a reason header field as the information element indicating the reason for the connection release, wherein the reason header field comprises a protocol information portion and a text portion understandable for a user and identifying the reason indicating the unavailability of radio resources, wherein the generating comprises generating the connection terminating message on the basis of a request identifier, a first information portion specifying a recipient of the request, a second information portion indicating the identity of the initiator of the request, a third information portion indicating a unique identifier to group together a series of messages, a fourth information portion identifying and ordering transactions set to the CSeq value that was stored for the direction from the calling to the called user, incremented by one, and a fifth information portion indicating routing information towards a party. determining (S10, S20), in a proxy call session control function (5; 13; 34), an unavailability of radio resources for the established connection of a party (1; 11; 41) and generating (S30; 120; 220), in the proxy call session control function, a connection terminating message (130; 230; 40) to be sent to at least one of the at least two parties, wherein the connection terminating message is provided with an information element indicating a reason for a connection release and indicating the unavailability of radio resources, and includes a reason header field as the information element indicating the reason for the connection release, wherein the reason header field comprises a protocol information portion and a text portion understandable for a user and identifying the reason indicating the unavailability of radio resources, wherein the generating comprises generating the connection terminating message on the basis of a request identifier, a first information portion specifying a recipient of the request, a second information portion indicating the identity of the initiator of the request, a third information portion indicating a unique identifier to group together a series of messages, a fourth information portion identifying and ordering transactions set to the CSeq value that was stored for the direction from the calling to the called user, incremented by one, and a fifth information portion indicating routing information towards a party. a request identifier, a first information portion specifying a recipient of the request, a second information portion indicating the identity of the initiator of the request, a third information portion indicating a unique identifier to group together a series of messages, a fourth information portion identifying and ordering transactions set to the CSeq value that was stored for the direction from the calling to the called user, incremented by one, and a fifth information portion indicating routing information towards a party.