diff --git a/sys/net/application_layer/gcoap/gcoap.c b/sys/net/application_layer/gcoap/gcoap.c
index 6d016f6519..b0494f7614 100644
--- a/sys/net/application_layer/gcoap/gcoap.c
+++ b/sys/net/application_layer/gcoap/gcoap.c
@@ -1657,6 +1657,9 @@ ssize_t gcoap_req_send(const uint8_t *buf, size_t len,
             ssize_t res = _cache_check(buf, len, memo, &cache_hit);
 
             if (res < 0) {
+                DEBUG("gcoap: Error from cache check");
+                memo->state = GCOAP_MEMO_UNUSED;
+                mutex_unlock(&_coap_state.lock);
                 return res;
             }
             len = res;
@@ -1667,6 +1670,9 @@ ssize_t gcoap_req_send(const uint8_t *buf, size_t len,
             /* Can't store it for retransmission, even though sending it from
              * the provided buffer once is possible */
             if (len > CONFIG_GCOAP_PDU_BUF_SIZE) {
+                DEBUG("gcoap: Request too large for retransmit buffer");
+                memo->state = GCOAP_MEMO_UNUSED;
+                mutex_unlock(&_coap_state.lock);
                 return -EINVAL;
             }