Issues with ISP DNS. Who has ideas?

Question

Domain Name System

Hello, does anyone have any ideas. The problem is this:
We are hosting the site xxx.xx, complaints began to come from the client that the site is allegedly sometimes not available. We started to explore. It turned out that the provider's DNS gives the following:

[email protected]:~$ host -a xxx.xx ns1.yyy.yy<br/>
Trying &quot;xxx.xx&quot;<br/>
Received 33 bytes from 111.222.333.444#53 in 17 ms<br/>
Trying &quot;xxx.xx&quot;<br/>
Using domain server:<br/>
Name: ns1.yyy.yy<br/>
Address: 111.222.333.444#53<br/>
Aliases: <br/>
<br/>
Host xxx.xx not found: 2(SERVFAIL)<br/>
Received 33 bytes from 111.222.333.444#53 in 17 ms

Google DNS and other third-party DNS give everything fine:

[email protected]:~$ host -a xxx.xx 8.8.8.8<br/>
Trying &quot;xxx.xx&quot;<br/>
Using domain server:<br/>
Name: 8.8.8.8<br/>
Address: 8.8.8.8#53<br/>
Aliases: <br/>
<br/>
;; -&gt;&gt;HEADER&lt;&lt;- opcode: QUERY, status: NOERROR, id: 95<br/>
;; flags: qr rd ra; QUERY: 1, ANSWER: 7, AUTHORITY: 0, ADDITIONAL: 0<br/>
<br/>
;; QUESTION SECTION:<br/>
;xxx.xx. IN ANY<br/>
<br/>
;; ANSWER SECTION:<br/>
xxx.xx. 3600 IN TXT &quot;v=spf1 ip4:444.333.222.111 a mx ~all&quot;<br/>
xxx.xx. 3600 IN SOA ns1.zzz.zz. zzz.zz. 2011022800 10800 3600 604800 86400<br/>
xxx.xx. 3600 IN NS ns1.zzz.zz.<br/>
xxx.xx. 3600 IN NS ns2.zzz.zz.<br/>
xxx.xx. 3600 IN MX 10 mail.xxx.xx.<br/>
xxx.xx. 3600 IN MX 20 mail.xxx.xx.<br/>
xxx.xx. 3600 IN A 444.333.222.111<br/>
<br/>
Received 213 bytes from 8.8.8.8#53 in 203 ms<br/>

Although other randomly selected domain names and DNS provider, and Google give normally. Does anyone have any ideas? Where have we blunted or settings of the provider's DNS? I will be grateful for any help.

Answer 1

Let's already here (or at least in a personal) all the information: the name of the provider, the name of the domain, etc.
Only Kashpirovsky can treat from a photograph.

Answer 2

As I understand it, the provider has a master DNS for your zone, since other DNS have your address in their cache, then it’s more likely that the provider has problems.
If it does not provide clarification, you can try other DNS. For example, the free Zoneedit.com.