I am getting this error while setting the alert on Grafana dashboard
lvl=eror msg=“Request error” logger=context userId=1 orgId=1 uname=admin error=“runtime error: index out of range [0] with length 0” stack="/usr/local/go/src/runtime/panic.go:88 (0x43aed2)\n/root/project/pkg/tsdb/azuremonitor/azuremonitor-datasource.go:378 (0x10a09ea)\n/usr/local/go/src/regexp/regexp.go:681 (0x7c1cb4)\n/usr/local/go/src/regexp/regexp.go:616 (0x7bc0b8)\n/usr/local/go/src/regexp/regexp.go:680 (0x7bc97c)\n/root/project/pkg/tsdb/azuremonitor/azuremonitor-datasource.go:352 (0x1098d4e)\n/root/project/pkg/tsdb/azuremonitor/azuremonitor-datasource.go:300 (0x109859c)\n/root/project/pkg/tsdb/azuremonitor/azuremonitor-datasource.go:61 (0x109421b)\n/root/project/pkg/tsdb/azuremonitor/azuremonitor.go:93 (0x1099ac6)\n/root/project/pkg/tsdb/request.go:17 (0xc3acd9)\n/root/project/pkg/services/alerting/conditions/query.go:158 (0x103bf19)\n/root/project/pkg/services/alerting/conditions/query.go:49 (0x103adea)\n/root/project/pkg/services/alerting/eval_handler.go:34 (0x102c41d)\n/root/project/pkg/services/alerting/test_rule.go:59 (0x1036e77)\n/root/project/pkg/services/alerting/test_rule.go:44 (0x1036d07)\n/usr/local/go/src/reflect/value.go:460 (0x49e0ca)\n/usr/local/go/src/reflect/value.go:321 (0x49d5d3)\n/root/project/pkg/bus/bus.go:128 (0xc171f8)\n/root/project/pkg/bus/bus.go:196 (0x168af21)\n/root/project/pkg/api/alerting.go:140 (0x168af2c)\n/usr/local/go/src/reflect/value.go:460 (0x49e0ca)\n/usr/local/go/src/reflect/value.go:321 (0x49d5d3)\n/root/go/pkg/mod/github.com/go-macaron/inject@v0.0.0-20160627170012-d8a0b8677191/inject.go:177 (0x976a2b)\n/root/go/pkg/mod/github.com/go-macaron/inject@v0.0.0-20160627170012-d8a0b8677191/inject.go:137 (0x976409)\n/root/project/pkg/api/common.go:37 (0x16e3b4d)\n/usr/local/go/src/reflect/value.go:460 (0x49e0ca)\n/usr/local/go/src/reflect/value.go:321 (0x49d5d3)\n/root/go/pkg/mod/github.com/go-macaron/inject@v0.0.0-20160627170012-d8a0b8677191/inject.go:177 (0x976a2b)\n/root/go/pkg/mod/github.com/go-macaron/inject@v0.0.0-20160627170012-d8a0b8677191/inject.go:137 (0x976409)\n/root/go/pkg/mod/gopkg.in/macaron.v1@v1.3.9/context.go:121 (0x9779b8)\n/root/go/pkg/mod/gopkg.in/macaron.v1@v1.3.9/context.go:112 (0x16257cc)\n/root/project/pkg/middleware/request_tracing.go:25 (0x16257bf)\n/usr/local/go/src/reflect/value.go:460 (0x49e0ca)\n/usr/local/go/src/reflect/value.go:321 (0x49d5d3)\n/root/go/pkg/mod/github.com/go-macaron/inject@v0.0.0-20160627170012-d8a0b8677191/inject.go:177 (0x976a2b)\n/root/go/pkg/mod/github.com/go-macaron/inject@v0.0.0-20160627170012-d8a0b8677191/inject.go:137 (0x976409)\n/root/go/pkg/mod/gopkg.in/macaron.v1@v1.3.9/context.go:121 (0x9779b8)\n/root/go/pkg/mod/gopkg.in/macaron.v1@v1.3.9/context.go:112 (0x1624fa0)\n/root/project/pkg/middleware/request_metrics.go:36 (0x1624f8b)\n/usr/local/go/src/reflect/value.go:460 (0x49e0ca)\n/usr/local/go/src/reflect/value.go:321 (0x49d5d3)\n/root/go/pkg/mod/github.com/go-macaron/inject@v0.0.0-20160627170012-d8a0b8677191/inject.go:177 (0x976a2b)\n/root/go/pkg/mod/github.com/go-macaron/inject@v0.0.0-20160627170012-d8a0b8677191/inject.go:137 (0x976409)\n/root/go/pkg/mod/gopkg.in/macaron.v1@v1.3.9/context.go:121 (0x9779b8)\n/root/go/pkg/mod/gopkg.in/macaron.v1@v1.3.9/context.go:112 (0x1624e52)\n/root/project/pkg/middleware/recovery.go:160 (0x1624e45)\n/root/go/pkg/mod/gopkg.in/macaron.v1@v1.3.9/context.go:79 (0x977860)\n/root/go/pkg/mod/github.com/go-macaron/inject@v0.0.0-20160627170012-d8a0b8677191/inject.go:157 (0x976757)\n/root/go/pkg/mod/github.com/go-macaron/inject@v0.0.0-20160627170012-d8a0b8677191/inject.go:135 (0x9764f8)\n/root/go/pkg/mod/gopkg.in/macaron.v1@v1.3.9/context.go:121 (0x9779b8)\n/root/go/pkg/mod/gopkg.in/macaron.v1@v1.3.9/context.go:112 (0x16221db)\n/root/project/pkg/middleware/logger.go:34 (0x16221c6)\n/usr/local/go/src/reflect/value.go:460 (0x49e0ca)\n/usr/local/go/src/reflect/value.go:321 (0x49d5d3)\n/root/go/pkg/mod/github.com/go-macaron/inject@v0.0.0-20160627170012-d8a0b8677191/inject.go:177 (0x976a2b)\n/root/go/pkg/mod/github.com/go-macaron/inject@v0.0.0-20160627170012-d8a0b8677191/inject.go:137 (0x976409)\n/root/go/pkg/mod/gopkg.in/macaron.v1@v1.3.9/context.go:121 (0x9779b8)\n/root/go/pkg/mod/gopkg.in/macaron.v1@v1.3.9/router.go:187 (0x988a36)\n/root/go/pkg/mod/gopkg.in/macaron.v1@v1.3.9/router.go:294 (0x9833ed)\n/root/go/pkg/mod/gopkg.in/macaron.v1@v1.3.9/macaron.go:220 (0x97c76a)\n/usr/local/go/src/net/http/server.go:2807 (0x706fc2)\n/usr/local/go/src/net/http/server.go:1895 (0x702a3b)\n/usr/local/go/src/runtime/asm_amd64.s:1373 (0x470180)\n"