Getting this?

2020/02/15 20:58:07 OSPF: [EC 134217740] Packet[DD]: Neighbor 192.168.0.1 Negotiation fails.

Clear up some space:

root@INTERNET-ROUTER:/jffs/ospf# ls -altri
total 668396
      1 drwxr-xr-x    9 root     root             0 Dec 31  1969 ..
     20 drwxr-xr-x    2 root     root             0 Dec 31  1969 .
     21 -rw——-    1 root     root     684436856 Feb 15 20:56 ospf.log
root@INTERNET-ROUTER:/jffs/ospf# du -sh ospf.log
652.7M  ospf.log
root@INTERNET-ROUTER:/jffs/ospf# df -h .
Filesystem                Size      Used Available Use% Mounted on
/dev/mtdblock/4          96.0M     94.8M      1.2M  99% /jffs
root@INTERNET-ROUTER:/jffs/ospf# >ospf.log
root@INTERNET-ROUTER:/jffs/ospf# df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/root                26.1M     26.1M         0 100% /
/dev/mtdblock/4          96.0M      5.6M     90.4M   6% /jffs
/dev/sda                  3.8G     33.4M      3.5G   1% /opt
root@INTERNET-ROUTER:/jffs/ospf# df -h .
Filesystem                Size      Used Available Use% Mounted on
/dev/mtdblock/4          96.0M      5.3M     90.7M   6% /jffs
root@INTERNET-ROUTER:/jffs/ospf# uptime
 20:57:47 up 16:00,  load average: 3.74, 2.76, 2.65
root@INTERNET-ROUTER:/jffs/ospf#

And consider disabling debug logging:

# cat /tmp/ospfd.conf
!
! Zebra configuration saved from vty
!   2019/12/13 08:12:53
!
frr version 7.1
frr defaults traditional
!
hostname INTERNET-ROUTER
domainname
log file /jffs/ospf/ospf.log
!
!debug ospf ism
!debug ospf nsm
!debug ospf lsa
!debug ospf zebra
!debug ospf nssa
!debug ospf packet all
!
!
!
!
router ospf
 ospf router-id 192.168.0.6
 log-adjacency-changes
 network 192.168.0.0/24 area 0
!
line vty
!
 

If that doesn't work, the solution on this page might be of help?

Cheers,
TK