I have a domain purchased from Google Domains. For my application to route to compute engine and using my domain, I changed the name servers to the Cloud DNS nameservers as suggested by the documentation here. However, this caused my GMail to stop working for that domain. I added NX records as suggested here, but emails are still not being sent to the GMail for the domain.
Here's a image to my DNS record for the full domain:
This image is DNS record for a subdomain.
Looks like you have some issues with DNS configuration. I've checked NS records for your domain bazilla.io and found something that could be the cause of your issue - there are no NS records accordingly to 8.8.8.8 and 1.1.1.1:
$ dig NS bazilla.io @8.8.8.8
; <<>> DiG 9.11.3-1ubuntu1.12-Ubuntu <<>> NS bazilla.io @8.8.8.8
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 63073
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;bazilla.io. IN NS
;; Query time: 132 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Mon Jun 08 18:37:44 UTC 2020
;; MSG SIZE rcvd: 39
$ dig NS bazilla.io @1.1.1.1
; <<>> DiG 9.11.3-1ubuntu1.12-Ubuntu <<>> NS bazilla.io @1.1.1.1
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 41198
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1452
;; QUESTION SECTION:
;bazilla.io. IN NS
;; Query time: 689 msec
;; SERVER: 1.1.1.1#53(1.1.1.1)
;; WHEN: Mon Jun 08 18:37:51 UTC 2020
;; MSG SIZE rcvd: 39
meanwhile no issues if you ask ns-cloud-b1.googledomains.com or ns-cloud-b2.googledomains.com:
$ dig NS bazilla.io @ns-cloud-b1.googledomains.com
; <<>> DiG 9.11.3-1ubuntu1.12-Ubuntu <<>> NS bazilla.io @ns-cloud-b1.googledomains.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 18061
;; flags: qr aa rd; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 1
;; WARNING: recursion requested but not available
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;bazilla.io. IN NS
;; ANSWER SECTION:
bazilla.io. 21600 IN NS ns-cloud-b1.googledomains.com.
bazilla.io. 21600 IN NS ns-cloud-b2.googledomains.com.
bazilla.io. 21600 IN NS ns-cloud-b3.googledomains.com.
bazilla.io. 21600 IN NS ns-cloud-b4.googledomains.com.
;; Query time: 8 msec
;; SERVER: 216.239.32.107#53(216.239.32.107)
;; WHEN: Mon Jun 08 18:39:19 UTC 2020
;; MSG SIZE rcvd: 160
$ dig NS bazilla.io @ns-cloud-b2.googledomains.com
; <<>> DiG 9.11.3-1ubuntu1.12-Ubuntu <<>> NS bazilla.io @ns-cloud-b2.googledomains.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 47841
;; flags: qr aa rd; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 1
;; WARNING: recursion requested but not available
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;bazilla.io. IN NS
;; ANSWER SECTION:
bazilla.io. 21600 IN NS ns-cloud-b1.googledomains.com.
bazilla.io. 21600 IN NS ns-cloud-b2.googledomains.com.
bazilla.io. 21600 IN NS ns-cloud-b3.googledomains.com.
bazilla.io. 21600 IN NS ns-cloud-b4.googledomains.com.
;; Query time: 8 msec
;; SERVER: 216.239.34.107#53(216.239.34.107)
;; WHEN: Mon Jun 08 18:40:13 UTC 2020
;; MSG SIZE rcvd: 160
To solve this issue you should go to Google Domains and set DNS servers for your domain by following documentation Manage domain name servers to:
ns-cloud-b1.googledomains.com
ns-cloud-b2.googledomains.com
ns-cloud-b3.googledomains.com
ns-cloud-b4.googledomains.com
and wait 24-48 hours for DNS propagation. You can check status of DNS propagation with online tools like dnsmap.io, dnschecker.org or other.
Accordingly to the documentation GCP Cloud DNS: Set up G Suite MX records you should configure 5 MX records:
MX server address Priority
ASPMX.L.GOOGLE.COM 1
ALT1.ASPMX.L.GOOGLE.COM 5
ALT2.ASPMX.L.GOOGLE.COM 5
ALT3.ASPMX.L.GOOGLE.COM 10
ALT4.ASPMX.L.GOOGLE.COM 10
but it's better to copy them from old DNS server.
You should remove extra records and/or duplicated from DNS zones.
In addition, there's no issue with your subdomain:
$ dig NS handson.bazilla.io @8.8.8.8
; <<>> DiG 9.11.3-1ubuntu1.12-Ubuntu <<>> NS handson.bazilla.io @8.8.8.8
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 52384
;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;handson.bazilla.io. IN NS
;; ANSWER SECTION:
handson.bazilla.io. 21599 IN NS ns-cloud-c1.googledomains.com.
handson.bazilla.io. 21599 IN NS ns-cloud-c2.googledomains.com.
handson.bazilla.io. 21599 IN NS ns-cloud-c3.googledomains.com.
handson.bazilla.io. 21599 IN NS ns-cloud-c4.googledomains.com.
;; Query time: 18 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Mon Jun 08 18:55:58 UTC 2020
;; MSG SIZE rcvd: 168
$ dig NS handson.bazilla.io @1.1.1.1
; <<>> DiG 9.11.3-1ubuntu1.12-Ubuntu <<>> NS handson.bazilla.io @1.1.1.1
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 37929
;; flags: qr rd ra; QUERY: 1, ANSWER: 4, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1452
;; QUESTION SECTION:
;handson.bazilla.io. IN NS
;; ANSWER SECTION:
handson.bazilla.io. 21600 IN NS ns-cloud-c1.googledomains.com.
handson.bazilla.io. 21600 IN NS ns-cloud-c2.googledomains.com.
handson.bazilla.io. 21600 IN NS ns-cloud-c3.googledomains.com.
handson.bazilla.io. 21600 IN NS ns-cloud-c4.googledomains.com.
;; Query time: 73 msec
;; SERVER: 1.1.1.1#53(1.1.1.1)
;; WHEN: Mon Jun 08 18:56:03 UTC 2020
;; MSG SIZE rcvd: 186
$ dig A handson.bazilla.io
; <<>> DiG 9.11.3-1ubuntu1.12-Ubuntu <<>> A handson.bazilla.io
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 41352
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 65494
;; QUESTION SECTION:
;handson.bazilla.io. IN A
;; ANSWER SECTION:
handson.bazilla.io. 299 IN A 34.107.144.39
;; Query time: 20 msec
;; SERVER: 127.0.0.53#53(127.0.0.53)
;; WHEN: Mon Jun 08 18:58:45 UTC 2020
;; MSG SIZE rcvd: 63
but still you should remove unnecessary MX records.