I submitted a manuscript to a journal one year ago. The journal is well known and has already published papers on the same subject including one of my previous papers. The paper I submitted went under review after two weeks. After eight months, I contacted the journal to inquire about the status of my manuscript, I got no response. I contacted the journal again after two months, and the managing editor informed me that the handling editor is trying to secure a referee for my paper. I sent another email three months later, the managing editor said that the handling editor is still trying to secure a referee for my paper. I asked them if I could suggest some referees and they agreed.
My question is: what should I do after this long waiting period?