3CX update to V20 not provisioning phone

[Alle CTEC]

I have a 3CX V18 18.0 Update 9 (Build 31) on premise control panel, I can't update it to V20, if I do it by updating the control panel or by making a backup, reinstalling and re-importing, I lose the provisioning with the phones, I noticed that the control panel, unlike the others, still offers me provisioning via IP and not just via FQDN and the link I attach is only http and not https http://xxx.3cx.it:5000/provisioning/nqpk3mdoml9/cfg{mac}

 

[Guillaume Bourgeois]

You are likely accessing the 3CX Dashboard/WebClient via the local IP of the PBX or FQDN without HTTPS, which is probably indicated by a red bar.
Is the Split DNS or Hairpin NAT configured?

 

[Alle CTEC]

I solved it like this. From V18 I deleted all the phones, I reset the phones and performed the provisioning on fqdn even if it was already like this. At this point I updated the control panel and everything works. I updated, I did not save the backup and reinstalled

 

[Alphabetic]

Your original port was 5001? Reinstalling took you to using 443 thats why you lost provisioning link

 

[Alle CTEC]

I tried both keeping 5001 and switching to 443, factory resetting the phone by deleting the phone from the user and reassigning it, but the phone was not provisioned in any way.