Error verifying phone number for grafana onCall. GET 400 Bad request, verification to number is blocked

Hello,
What are steps to solve this error? Are only US numbers supported?

I got error in dev console as i entered my phone number(Bangladesh) for verification, and clicked “send code”

I get 2 errors: GET 400 Bad request and verification to number is blocked.

Uncaught (in promise) Verification to +8801725500000 is blocked
Promise.then (async)		
eval	@	PhoneVerification.tsx:135
q4	@	PhoneVerification.module.css:27
i	@	PhoneVerification.module.css:27
Promise.then (async)		
q4	@	PhoneVerification.module.css:27
i	@	PhoneVerification.module.css:27
eval	@	PhoneVerification.module.css:27
eval	@	PhoneVerification.module.css:27
eval	@	PhoneVerification.tsx:118
Promise.then (async)		
then	@	recaptcha__en.js:284
eval	@	PhoneVerification.tsx:118
setTimeout (async)		
(anonymous)	@	recaptcha__en.js:317
(anonymous)	@	recaptcha__en.js:509
eval	@	PhoneVerification.tsx:115
q4	@	PhoneVerification.module.css:27
i	@	PhoneVerification.module.css:27
eval	@	PhoneVerification.module.css:27
eval	@	PhoneVerification.module.css:27
eval	@	PhoneVerification.tsx:105
onClick	@	PhoneVerification.tsx:367
Zt	@	react-dom.production.min.js:54
rn	@	react-dom.production.min.js:54
Xt	@	react-dom.production.min.js:55
ui	@	react-dom.production.min.js:105
ze	@	react-dom.production.min.js:106
(anonymous)	@	react-dom.production.min.js:117
Oc	@	react-dom.production.min.js:274
Mt	@	react-dom.production.min.js:52
Hn	@	react-dom.production.min.js:109
jt	@	react-dom.production.min.js:74
bt	@	react-dom.production.min.js:73
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This is the other error. Both in browser dev console:

GET https://tntla.grafana.net/api/plugin-proxy/grafana-oncall-app/api/internal/v1/users/U9NIA8Y/get_verification_code/ 400 (Bad Request)
e.<computed>.e.<computed>	@	(index):1
eval	@	http-client.ts:70
Qd	@	index.js:176
i	@	index.js:176
eval	@	index.js:176
eval	@	index.js:176
eval	@	http-client.ts:23
i	@	index.js:34
GET	@	index.js:72
eval	@	user.helpers.tsx:65
sM	@	http-client.ts:102
i	@	http-client.ts:102
eval	@	http-client.ts:102
eval	@	http-client.ts:102
fetchVerificationCode	@	user.helpers.tsx:64
eval	@	PhoneVerification.tsx:135
q4	@	PhoneVerification.module.css:27
i	@	PhoneVerification.module.css:27
Promise.then (async)		
q4	@	PhoneVerification.module.css:27
i	@	PhoneVerification.module.css:27
eval	@	PhoneVerification.module.css:27
eval	@	PhoneVerification.module.css:27
eval	@	PhoneVerification.tsx:118
Promise.then (async)		
then	@	recaptcha__en.js:284
eval	@	PhoneVerification.tsx:118
setTimeout (async)		
(anonymous)	@	recaptcha__en.js:317
(anonymous)	@	recaptcha__en.js:509
eval	@	PhoneVerification.tsx:115
q4	@	PhoneVerification.module.css:27
i	@	PhoneVerification.module.css:27
eval	@	PhoneVerification.module.css:27
eval	@	PhoneVerification.module.css:27
eval	@	PhoneVerification.tsx:105
onClick	@	PhoneVerification.tsx:367
Zt	@	react-dom.production.min.js:54
rn	@	react-dom.production.min.js:54
Xt	@	react-dom.production.min.js:55
ui	@	react-dom.production.min.js:105
ze	@	react-dom.production.min.js:106
(anonymous)	@	react-dom.production.min.js:117
Oc	@	react-dom.production.min.js:274
Mt	@	react-dom.production.min.js:52
Hn	@	react-dom.production.min.js:109
jt	@	react-dom.production.min.js:74
bt	@	react-dom.production.min.js:73