Same problem here. Looks like OpenVPN Connect crashes as the logs show the following exactly when the popup with the error appears:
2018-33-23 14:33:51 1
2018-33-23 14:33:51 ----- OpenVPN Start -----
OpenVPN core 3.2 ios arm64 64-bit PT_PROXY built on Sep 4 2018 09:41:09
2018-33-23 14:33:51 Frame=512/2048/512 mssfix-ctrl=1250
2018-33-23 14:33:51 UNUSED OPTIONS
1 [resolv-retry] [infinite]
3 [nobind]
6 [allow-pull-fqdn]
7 [pull]
8 [tls-client]
11 [tls-cipher] [TLS-DHE-RSA-WITH-AES-256-GCM-SHA384]
16 [verify-x509-name] [opr-vpn-server@ls] [name]
17 [auth-retry] [nointeract]
19 [verb] [4]
20 [mute] [10]
2018-33-23 14:33:51 EVENT: RESOLVE
@ordex, do you already know what's going on?