Regular Issues with Email Fetching via IMAP in Freescout

[vadim]

The same email works with email client, problem only with Freescout

[vadim]

In case fetching problem I have in log this situation for all domain use emails. Cloudron reboot resolve problem. I have to reboot Cloudron for many times per day now fetching works.

[vadim]

I moved domain names to CloudFlare and it works for 10 hours without errors.

[girish]

Ah ok, so maybe some issue with the nameservers.

[vadim]

Problem came back in few hours! I have good hardware. What is the problem could be?

[girish]

@vadim how have you configured the freescout IMAP connection ? Is FreeScout and Cloudron mail on the same server ?

[vadim]

Yes, it is on the same server. In case this problem button Check Connection also gives error. After reboot starting to work for some hours and again stops

[girish]

@vadim See https://docs.cloudron.io/apps/freescout/#cloudron-mailbox . Use SSL in the Encryption dropdown . FreeScout has a bit different terminology than one expects.

[vadim]

I tried also with SSL and I have been used SSL, the problem started with SSL and now I am trying with TLS.
Actually problem is Cloudron blocks some connections, my PTR record also is not reached by Cloudron, but it is OK, and I am sure, I checked it.

In this moment, when the problem is Active I have next situation:

sudo cloudron-support --troubleshoot
[OK]	node version is correct
[OK]	docker is running
[OK]	MySQL is running
[OK]	nginx is running
[OK]	box is running
[OK]	unbound is running
[FAIL]	Could not load dashboard domain.
Hairpin NAT is not working. Please check if your router supports it
test@test:~$ host my.emailserver.eu
Host my.emailserver.eu not found: 2(SERVFAIL)

NAT in my router is set up correctly, I am sure! Other services work perfect!

I need just to reboot server and after cloudron reboot it immediately starting to work.

sudo cloudron-support --troubleshoot
[OK]	node version is correct
[OK]	docker is running
[OK]	MySQL is running
[OK]	nginx is running
[OK]	box is running
[OK]	unbound is running
[OK]	Dashboard is reachable via domain name

test@test:~$ host my.emailserver.eu
my.emailserver.eu has address 213.my.ip.address

[girish]

@vadim OK, so, the root cause is the DNS resolution issue . Looks like it starts to fail at some point. Is there something in the network that blocks DNS requests?

Looks like this is some internal network? Maybe try to set up a forward zone to the internal DNS (https://docs.cloudron.io/networking/#internal-dns-server) ? In the next release, we are moving away from unbound since it's causing not-so-easily debuggable situations (like this one).