Refunding results in Communications Error

While regular sales seem to work fine, whenever I try to refund a product I get a "Communications Error" from the terminal. Might be an issue with the terminal setup, but may be worth looking into.

Heres the request and response.

Request:
<TRANS><REQUEST_TYPE>00</REQUEST_TYPE><ACTION_TYPE>10</ACTION_TYPE><CLIENT>#########</CLIENT><LOCATION>0000</LOCATION><REGISTER>1</REGISTER><CASHIER>1</CASHIER><REQ_TRANS_ID>276334</REQ_TRANS_ID><AMOUNT>2420</AMOUNT></TRANS>


Response:
<TRANS><PAYLinqTransId>1635713453416</PAYLinqTransId><reqtransid>276334</reqtransid><CheckNumber>276334</CheckNumber><TransRespCode>11</TransRespCode><TransRespMsg>Communication Error</TransRespMsg><CardNo></CardNo><CardTypeUsed></CardTypeUsed><InvoiceNumber></InvoiceNumber><ProviderTransID></ProviderTransID><CardBalance></CardBalance><CardExpDate></CardExpDate><ProcessedAmount></ProcessedAmount><cardentrymode></cardentrymode><CardCode>UNKNOWN</CardCode><MerchantReceipt></MerchantReceipt><CustomerReceipt></CustomerReceipt><ServerNumber>1</ServerNumber><TipAmt></TipAmt><Signature></Signature><MimeType></MimeType><EmvName></EmvName><EmvAid></EmvAid><EmvTvr></EmvTvr><EmvTsi></EmvTsi><Trace></Trace><MEndorse></MEndorse><CEndorse></CEndorse><Header></Header><Footer></Footer><Account></Account><CustLang></CustLang><Token></Token><TokenExp></TokenExp><TransactionCode></TransactionCode><SurCharge></SurCharge><SignatureReq></SignatureReq><CvmResult></CvmResult><CustomerReference></CustomerReference><DebitRRN></DebitRRN><DeviceID></DeviceID><TableNumber></TableNumber><TransactionStatus></TransactionStatus><TerminalReference></TerminalReference><HostResponseMsg></HostResponseMsg><HostResponseCode></HostResponseCode><BatchNo></BatchNo><TerminalID></TerminalID><MerchantID></MerchantID><CustomerName></CustomerName><CustomerCardDescription></CustomerCardDescription></TRANS>