fail with site to site vpn

hello an thanks to all for helping me, i have a trouble with mi vpn site to site, in my configuration i have 4 tunnels vpn between sites, 2 works in the wan 1 and the others in wan 2, and have a zone vpn with ospf, they work fine but few weeks ago they start to fail, when i turn on both wan, two of that tunnels go down, the same with the other wan, i can`t find wheare is the problem i look everywhere, i change distance, priority, and ospf parameter but nothing work, with all in enable, only 2 tunnels stay up an the other 2 in down and made fase 2 success.

i hope you can help me. really thanks.